Linux Debian cheat sheet

cheat sheets

cheat sheet cmd

curl cheat.sh/ls

TooLongDontRead

# npm install -g tldr
tldr ls

how to

# npm install -g how-2
how2 ls

Security cheat sheet

commands gnu commands

time 
# run GNU version of the command:
/etc/bin/time
# or 
\time

retrieve human readable information from binary files

strings /usr/share/teams/libEGL.so | grep git

place for scripts, permanent script

### system wide for all users
### /etc/profile is only run at login
### ~/.profile file runs each time a new shell is started 
# System-wide .bashrc file for interactive bash(1) shells.
/etc/bash.bashrc
# system-wide .profile file for the Bourne shell sh(1)
/etc/profile
/etc/environment
/etc/profile.d/my_new_update.sh

### during user login
~/.bash_profile
# executed by Bourne-compatible login shells.
~/.profile 

# during open the terminal, executed by bash for non-login shells.
~/.bashrc

socket proxy, proxy to remote machine

ssh -D <localport> <user>@<remote host>

and checking if it is working for 'ssh -D 7772 cherkavi@15pos1.190.211.1'

ssh -o "ProxyCommand nc -x 127.0.0.1:7772 %h %p" cherkavi@151.190.211.47

jumpserver proxy jump host bastion

# ssh root@35.35.13.49 -o "proxycommand ssh -W %h:%p -i /home/admin/.ssh/identity-bastionhost ubuntu@10.0.12.10"  -t "su - admin" 
# ssh root@35.35.13.49 -t "su admin"  ssh -i /home/admin/.ssh/identity-bastionhost ubuntu@10.0.12.10
# ssh root@35.35.13.49 "su admin && ssh -i /home/admin/.ssh/identity-bastionhost ubuntu@10.0.12.10"
# ssh root@35.35.13.49 -t "su admin" "ssh -i /home/admin/.ssh/identity-bastionhost ubuntu@10.0.12.10"
# ssh root@35.35.13.49 -t "su admin"  ubuntu@10.0.12.10

# localhost ---->  35.35.13.49 ---->   10.0.12.10
# all identity files must be placed on localhost !!!
ssh -Ao ProxyCommand="ssh -W %h:%p -p 22 $PROD_BASTION_USER@$PROD_BASTION_HOST" -i $EC2_INVENTORY -p EC2_AIRFLOW_PORT $EC2_AIRFLOW_USER@$EC2_AIRFLOW_HOST $*

scp bastion scp proxy scp copy via bastion

scp -o "ProxyCommand ssh -W %h:%p -p 22 $PROD_BASTION_USER@$PROD_BASTION_HOST" -i $EC2_KEY 1.md $EC2_USER@$EC2_HOST:~/

scp error

bash: scp: command not found

solution: scp should be installed on both!!! hosts

tunnel, port forwarding from local machine to outside

ssh -L <local_port>:<remote_host from ssh_host>:<remote_port> <username>@<ssh_host>
# ssh -L 28010:remote_host:8010 user_name@remote_host
ssh -L <local_port>:<remote_host from ssh_host>:<remote_port> <ssh_host>
# ssh -L 28010:vldn337:8010 localhost

# destination service on the same machine as ssh_host
# localport!=remote_port (28010!=8010)
ssh -L 28010:127.0.0.1:8010 user_name@remote_host

from local port 7000 to remote 5005

ssh -L 7000:127.0.0.1:5005 cherkavi@134.190.200.201

browser(ext_host) -> 134.190.2.5 -> 134.190.200.201

user@134.190.2.5:~$ ssh -L 134.190.2.5:8091:134.190.200.201:8091 cherkavi@134.190.200.201
user@ext_host:~$ wget 134.190.2.5:8091/echo

tunnel, port forwarding from outside to localmachine

# ssh -R <remoteport>:<local host name>:<local port> <hostname>
# localy service on port 9092 should be started
# and remotelly you can reach it out just using 127.0.0.1:7777
ssh -R 7777:127.0.0.1:9092 localhost

tunnel for remote machine with proxy, local proxy for remote machine, remote proxy access

//TODO local=======>remote
after that, remote can use local as proxy

first of all start local proxy (proxychains or redsock)

sudo apt install privoxy
sudo vim /etc/privoxy/config
# listen-address  127.0.0.1:9999
# forward-socks5t / http://my-login:passw@proxy.zur:8080 .
# forward-socks4a / http://my-login:passw@proxy.zur:8080 .
# or 
# forward   /      http://my-login:passw@proxy.zur:8080
systemctl start privoxy

# locally proxy server on port 9999 should be started
ssh -D 9999 127.0.0.1 -t ssh -R 7777:127.0.0.1:9999 username@192.118.112.13

# from remote machine you can execute 
wget -e use_proxy=yes -e http_proxy=127.0.0.1:7777 https://google.com

ssh suppress banner, ssh no invitation

ssh -q my_server.org

ssh verbosive, ssh log, debug ssh

ssh -vv my_server.org

ssh variable ssh envvar ssh send variable

ssh variable in command line

ssh -t user@host VAR1="Petya" bash -l

sshd config

locally: ~/.ssh/config

SendEnv MY_LOCAL_VAR

remotely: /etc/ssh/sshd_config

AcceptEnv MY_LOCAL_VAR

ssh environment, execute on remote server bash file after login

echo "VAR1=Hello" > sshenv
echo "VAR2=43" >> sshenv
scp sshenv user@server:~/.ssh/environment
ssh user@server myscript

ssh run command

ssh -t user@host 'bash -s' < my-script.sh
# with arguments
ssh -t user@host 'bash -s' -- < my-script.sh arg1 arg2 arg3
# ssh document here 
ssh -T user@host << _dochere_marker
cd /tmp
echo $(date) >> visit-marker.txt
_dochere_marker

local proxy cntlm, cntlm proxy

  app_1 --.
           \
  app_2 --- ---> local proxy <---> External Proxy <---> WWW
   ...     /
  app_n --'

install cntlm

# temporarily set proxy variables for curl and brew to work in this session
$ export http_proxy=http://<user>:<password>@proxy-url:proxy-port
$ export https_proxy=$http_proxy

# update & upgrade apt
$ sudo --preserve-env=http_proxy,https_proxy apt-get update
$ sudo --preserve-env=http_proxy,https_proxy apt-get upgrade

# finally, install cntlm
sudo --preserve-env=http_proxy,https_proxy apt-get install cntlm

edit configuration

vim ~/.config/cntlm/cntlm.conf

Username user-name
Domain  domain-name
Proxy   proxy-url:proxy-port
NoProxy localhost, 127.0.0.*, 10.*, 192.168.*, *.zur
Listen  3128

or globally

sudo vim /etc/cntlm.conf

~/bin/proxy-start.sh

#!/bin/sh

pidfile=~/.config/cntlm/cntlm.pid

if [ -f $pidfile ]; then
kill "$(cat $pidfile)"
sleep 2
fi

cntlm -c ~/.config/cntlm/cntlm.conf -P $pidfile -I

source ~/bin/proxy-settings.sh

proxy_url="http://127.0.0.1:3128"
export http_proxy=$proxy_url
export https_proxy=$http_proxy
export HTTP_PROXY=$http_proxy
export HTTPS_PROXY=$http_proxy

export _JAVA_OPTIONS="-Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttps.proxyHost=127.0.0.1 -Dhttps.proxyPort=3128 -Dhttps.nonProxyHosts=localhost|*.ubsgroup.net|*.muc -Dhttp.nonProxyHosts=localhost|*.ubsgroup.net|*.zur"

check status

sudo invoke-rc.d cntlm status
ss -lt | grep 3128

possible solution to detect remote client to your machine

# open access
ping -s 120 -c 1 146.255.193.66
ping -s 121 -c 1 146.255.193.66
ping -s 122 -c 1 146.255.193.66

# close access
ping -s 123 -c 1 146.255.193.66

open ports, open connections, listening ports, application by port, application port, process port, pid port

# list of open files
sudo lsof -i -P -n | grep LISTEN
# list of files for specific user
lsof -u my_own_user 

# limit of files for user
ulimit -a


# list of open connections
sudo netstat -tulpan | grep LISTEN
sudo ss -tulwn | grep LISTEN

# list of open ports
sudo nmap -sT -O 127.0.0.1

# print pid of process that occupying 9999 port
sudo ss -tulpan 'sport = :9999'

# open input output
iotop

# list of services mapping service to port mapping port to service
less /etc/services

mount drive to path mount

# <drive> <path>
sudo mount /dev/sdd /tin

mount remote filesystem via ssh, map folder via ssh, ssh remote folder

sudo mkdir /mnt/vendor-cluster-prod
sudo sshfs -o allow_other,IdentityFile=~/.ssh/id_rsa vcherkashyn@190.17.19.11:/remote/path/folder /mnt/vendor-cluster-prod
# sudo fusermount -u /remote/path/folder
# sudo umount /remote/path/folder

mount remote filesystem via ftp

sudo apt install curlftpfs
sudo mkdir /mnt/samsung-note
curlftpfs testuser:testpassword@192.168.178.20:2221 /mnt/samsung-note/

samsung phone android phone folder

cd /run/user/1000/gvfs
# phone samsung
cd /run/user/1000/gvfs/mtp:host=SAMSUNG_SAMSUNG_Android_RFxxxxxxxxx

mount windows folder, mount windows shared folder

sudo apt install nfs-common
sudo apt install cifs-utils

sudo mkdir -p /mnt/windows-computer
USER_NAME='my-username'
USER_DOMAIN='ZUR'
USER_SERVER='//u015029.ubsbank.net/home$/x453337/'
sudo mount -t cifs -o auto,gid=$(id -g),uid=$(id -u),username=$USER_NAME,domain=$USER_DOMAIN,vers=2.1 $USER_SERVER /mnt/windows-computer

mount issue

bad option;  for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.

sudo apt-get install nfs-common
sudo apt-get install cifs-utils

mount usb drive temporary mount disk

sudo mount /dev/sdd    /media/tina-team

unmount usb detach usb

umount /dev/sdd

mount usb drive permanently mount, map drive

sudo mkdir /mnt/disks/k8s-local-storage1
sudo chmod 755 /mnt/disks/k8s-local-storage1
sudo ln -s /mnt/disks/k8s-local-storage1/nfs nfs1
ls -la /mnt/disks
ls -la /mnt

sudo blkid
sudo vim /etc/fstab
# add record
# UUID=42665716-1f89-44d4-881c-37b207aecb71 /mnt/disks/k8s-local-storage1 ext4 defaults 0 0

# refresg fstab reload
sudo mount -av
ls /mnt/disks/k8s-local-storage1

option 2

sudo vim /etc/fstab
# add line
# /dev/disk/by-uuid/8765-4321    /media/usb-drive         vfat   0   0

# copy everything from ```mount```
# /dev/sdd5 on /media/user1/e91bd98f-7a13-43ef-9dce-60d3a2f15558 type ext4 (rw,nosuid,nodev,relatime,uhelper=udisks2)
# /dev/sda1 on /media/kali/usbdata type fuseblk (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096,uhelper=udisks2)

# systemctl daemon-reload

sudo mount -av

mount remote drive via network

10.55.0.3:/mnt/disks/k8s-local-storage/nfs /mnt/nfs nfs rw,noauto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14 0 0

drive uuid hdd uuid

blkid

list drives, drive list, attached drives

lsblk
fdisk -l

create filesystem, format drive

sudo mkfs -t xfs /dev/xvdb

sudo mke2fs /dev/xvdb

gpg signature check, asc signature check, crt signature check

kgpg --keyserver keyserver.ubuntu.com --recv-keys 9032CAE4CBFA933A5A2145D5FF97C53F183C045D
gpg --import john-brooks.asc

gpg --verify ricochet-1.1.4-src.tar.bz2.asc

in case of error like:

gpg: Can't check signature: No public key

gpg --import gpg-pubkey.txt
gpg --verify openldap-2.5.13.tgz.asc

authenticator 2fa

sudo apt install oathtool
oathtool -b --totp $CODE_2FA

oathtool: base32 decoding failed: Base32 string is invalid

connect to remote machine via ssh without credentials

# generate new RSA keys, create RSA, generate keys
ssh-keygen -t rsa
ssh-keygen -t rsa -b 4096 -f /tmp/my_ssh_key

( check created file /home/{user}/.ssh/id_rsa )

# if you have copied it, check permissions
chmod 700 ~/.ssh
chmod 700 ~/.ssh/*

print public ssh keys, ssh public keys

cat ~/.ssh/id_rsa.pub

passphrase skip typing ssh-keygen without passphrase, avoid Enter passphrase for key

eval `ssh-agent -s` 
ssh-add $HOME/.ssh/id_rsa

login without typing password

# ssh
sshpass -p my_password ssh my_user@192.178.192.10
sshpass -p my_password ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null my_user@192.178.192.10
# ftp 
sshpass -p $CHINA_PASS sftp -P $CHINA_JUMP_SERVER_PORT $CHINA_USER@$CHINA_JUMP_SERVER

login without typing password

echo $my_password | ssh my_user@192.178.192.10

copy ssh key to remote machine,

ssh-copy-id {username}@{machine ip}:{port}
ssh-copy-id -i ~/.ssh/id_rsa.pub -o StrictHostKeyChecking=no vcherkashyn@bmw000013.adv.org
# manual execution
cat ~/.ssh/id_rsa.pub | ssh vcherkashyn@bmw000013.adv.org 'cat >> ~/.ssh/authorized_keys'

# output nothing when ssh key exists, ssh check
ssh-copy-id user@ubssp000013.vantagedp.com 2>/dev/null

after copying you can use ssh connection with inventory file

# id_rsa - your private key 
ssh -i ~/.ssh/id_rsa vcherkashyn@bmw000013.adv.org

automate copying password

./ssh-copy.expect my_user ubsad00015.vantage.org "my_passw"

#!/usr/bin/expect -f
set user [lindex $argv 0];
set host [lindex $argv 1];
set password [lindex $argv 2];

spawn ssh-copy-id $user@$host
expect "])?"
send "yes\n"
expect "password: "
send "$password\n"
expect eof

sometimes need to add next

ssh-agent bash
ssh-add ~/.ssh/id_dsa or id_rsa

remove credentials ( undo previous command )

ssh-keygen -f "/home/{user}/.ssh/known_hosts" -R "10.140.240.105"

copy ssh key to remote machine, but manually:

cat .ssh/id_rsa.pub | ssh {username}@{ip}:{port} "cat >> ~/.ssh/authorized_keys"
chmod 700 ~/.ssh ;
chmod 600 ~/.ssh/authorized_keys

issue broken pipe ssh

vim ~/.ssh/config

Host *
    ServerAliveInterval 30
    ServerAliveCountMax 5

ssh fingerprint checking

ssh -o StrictHostKeyChecking=no user@ubsp00013.vantage.org
sshpass -p my_password ssh -o StrictHostKeyChecking=no my_user@ubsp00013.vantage.org

# check ssh-copy-id, check fingerprint
ssh-keygen -F bmw000013.adv.org
# return 0 ( and info line ), return 1 when not aware about the host

manage multiply keys

$ ls ~/.ssh
-rw-------  id_rsa
-rw-------  id_rsa_bmw
-rw-r--r--  id_rsa_bmw.pub
-rw-r--r--  id_rsa.pub

$ cat ~/.ssh/config 
IdentityFile ~/.ssh/id_rsa_bmw
IdentityFile ~/.ssh/id_rsa

copy from local machine to remote one, remote copy

scp filename.txt cherkavi@129.191.200.15:~/temp/filename-from-local.txt

sshpass -p $CHINA_PASS scp -P $CHINA_JUMP_SERVER_PORT 1.txt $CHINA_USER@$CHINA_JUMP_SERVER:
sshpass -p $CHINA_PASS scp -P $CHINA_JUMP_SERVER_PORT 1.txt $CHINA_USER@$CHINA_JUMP_SERVER:~/
sshpass -p $CHINA_PASS scp -P $CHINA_JUMP_SERVER_PORT 1.txt $CHINA_USER@$CHINA_JUMP_SERVER:~/1.txt

copy from remote machine to local

scp -r cherkavi@129.191.200.15:~/temp/filename-from-local.txt filename.txt 
scp -i $EC2_KEY -r ubuntu@35.175.255.10:~/airflow/logs/shopify_product_create/product_create/2021-07-17T02:31:19.880705+00:00/1.log 1.log

copy directory to remote machine, copy folder to remote machine

scp -pr /source/directory user@host:the/target/directory

the same as local copy folder

cp -var /path/to/folder /another/path/to/folder

copy file with saving all attributes, copy attributes, copy file with attributes

cp -r --preserve=mode,ownership,timestamps /path/to/src /path/to/dest
cp -r --preserve=all /path/to/src /path/to/dest

copy only when changed

cp --checksum /path/to/src /path/to/dest

change owner

# change owner recursively for current folder and subfolders
sudo chown -R $USER .

rsync singe file copy from remote

#!/bin/bash

if [[ $FILE_PATH == "" ]]; then
    echo "file to copy: $FILE_PATH"
else
    if [[ $1 == "" ]]; then
    	echo "provide path to file or env.FILE_PATH"
    else
        FILE_PATH=$1
    fi
fi

USER_CHINA=cherkavi
HOST=10.10.10.1

scp -r $USER_CHINA@$HOST:$FILE_PATH .
# rsync -avz --progress  $USER_CHINA@$HOST:$FILE_PATH $FILE_PATH

sync folders synchronize folders, copy everything between folders, diff folder

!!! rsync has direction from to

# print diff 
diff -qr /tmp/first-folder/ /tmp/second-folder

# local sync
rsync -r /tmp/first-folder/ /tmp/second-folder
## Attributes Verbosive Unew-modification-time
rsync -avu /tmp/first-folder/ /tmp/second-folder

# sync remote folder to local ( copy FROM remote )
rsync -avz user@ubspdesp013.vantage.org:~/test-2020-02-28  /home/projects/temp/test-2020-02-28
# sync remote folder to local ( copy FROM remote ) with specific port with compression
rsync -avz -e 'ssh -p 2233' user@ubspdesp013.vantage.org:~/test-2020-02-28  /home/projects/temp/test-2020-02-28

# sync local folder to remote ( copy TO remote )
rsync -avz /home/projects/temp/test-2020-02-28  user@ubspdesp013.vantage.org:~/test-2020-02-28  
# sync local folder to remote ( copy TO remote ) include exclude
rsync -avz --include "*.txt" --exclude "*.bin" /home/projects/temp/test-2020-02-28  user@ubspdesp013.vantage.org:~/test-2020-02-28  

# sync via bastion
rsync -avz -e 'ssh -Ao ProxyCommand="ssh -W %h:%p -p 22 $PROD_BASTION_USER@$PROD_BASTION_HOST" -i '$EC2_KEY $SOURCE_FOLDER/requirements.txt $EC2_LIST_COMPARATOR_USER@$EC2_LIST_COMPARATOR_HOST:~/list-comparator/requirements.txt

function cluster-prod-generation-sync-to(){
  if [[ $1 == "" ]]; then
      return 1
  fi
  rsync -avz . $USER_GT_LOGIN@ubsdpd00013.vantage.org:~/$1
}

create directory on remote machine, create folder remotely, ssh execute command, ssh remote execution

ssh user@host "mkdir -p /target/path/"

ssh execute command and detach ssh execute detached ssh command SIGHUP Signal Hang UP

each_node="bpde00013.ubsbank.org"
REMOTE_SCRIPT="/opt/app/1.sh"
REMOTE_OUTPUT_LOG="/var/log/1.output"

ssh $REMOTE_USER"@"$each_node "nohup $REMOTE_SCRIPT </dev/null > $REMOTE_OUTPUT_LOG 2>&1 &"

ssh xserver, ssh graphical

option1

deamon settings

vim /etc/ssh/sshd_config
sudo systemctl restart sshd

X11Forwarding yes

connect with X11 forwarding

ssh -X username@server.com

option 2

export DISPLAY=:0.0
xterm

here document, sftp batch command with bash

sftp -P 2222 my_user@localhost << END_FILE_MARKER
ls
exit
END_FILE_MARKER

env variable enviroment variables replace

echo "${VAR_1}" | envsubst
envsubst < path/to/file/with/variables > path/to/output/file

map folder to another path, mount dir to another location

# map local /tmp folder to another path/drive
sudo mount -B /tmp /mapped_drive/path/to/tmp

mount cdrom ( for virtual machine )

sudo mount /dev/cdrom /mnt

create ram disc

mkdir -p /mnt/my-ram
mount -t tmpfs tmpfs /mnt/my-ram -o size=1024M

repeat command with predefined interval, execute command repeatedly, watch multiple command watch pipe

watch -n 60 'ls -la | grep archive'

execute command in case of changes watch file

ls *.txt | entr firefox

repeat last command

!!

repeat last command with substring "flow" included into whole command line

!?flow

execute in current dir, inline shell execution

. goto-command.sh

directories into stack

pushd
popd
dirs

to previous folder

cd -

sudo reboot

shutdown -r now

sort, order

# simple sort
sort <filename>

#  sort by column ( space delimiter )
sort -k 3 <filename>

# sort by column number, with delimiter, with digital value ( 01, 02....10,11 )
sort -g -k 11 -t "/" session.list

# sort with reverse order
sort -r <filename>

print file with line numbers, output linenumbers

cat -n <filename>

split and join big files split and merge, make parts from big file copy parts

split --bytes=1M /path/to/image/image.jpg /path/to/image/prefixForNewImagePieces
# --bytes=1G

cat prefixFiles* > newimage.jpg

cut big file, split big file, cat after threshold

cat --lines=17000 big_text_file.txt

unique lines (duplications) into file

add counter and print result

uniq --count

duplicates

print only duplicates ( distinct )

uniq --repeated

print all duplications

uniq -D

unique

uniq --unique

output to columns format output to column

ls | column -t -c

print column from file, split string with separator

cut --delimiter "," --fields 2,3,4 test1.csv
cut --delimiter "," -f2,3,4 test1.csv

substring with fixed number of chars: from 1.to(15) and 1.to(15) && 20.to(50)

cut -c1-15
cut -c1-15,20-50

output to file without echo on screen, echo without typing on screen

echo "text file" | grep "" > $random_script_filename

system log information, logging

# read log
tail -f /var/log/syslog
# write to system log
echo "test" | /usr/bin/logger -t cronjob
# write log message to another system
logger --server 192.168.1.10 --tcp "This is just a simple log line"

/var/log/messages

commands execution logging session logging

# write output of command to out.txt and execution time to out-timing.txt
script out.txt --timing=out-timing.txt

repository list of all repositories

sudo cat /etc/apt/sources.list*

add repository

add-apt-repository ppa:inkscape.dev/stable

you can find additional file into

/etc/apt/sources.list.d

or manually add repository

# https://packages.debian.org/bullseye/amd64/skopeo/download
# The following signatures couldn't be verified because the public key is not available
# deb [trusted=yes] http://ftp.at.debian.org/debian/ bullseye main contrib non-free

remove repository

sudo add-apt-repository -r ppa:danielrichter2007/grub-customizer

search after adding

apt-cache search inkscape

update from one repo, single update

sudo apt-get update -o Dir::Etc::sourcelist="sources.list.d/cc-ros-mirror.list" -o Dir::Etc::sourceparts="-" -o APT::Get::List-Cleanup="0"

remove repository

sudo rm /etc/apt/sources.list.d/inkscape.dev*

avoid to put command into history, hide password into history, avoid history

add space before command

history settings history ignore duplicates history datetime

HISTTIMEFORMAT="%Y-%m-%d %T "
HISTCONTROL=ignoreboth
history

bash settings, history lookup with arrows, tab autocomplete

~/.inputrc

"\e[A": history-search-backward
"\e[B": history-search-forward
set show-all-if-ambiguous on
set completion-ignore-case on
TAB: menu-complete
"\e[Z": menu-complete-backward
set show-all-if-unmodified on
set show-all-if-ambiguous on

script settings

# stop execution when non-zero exit
set -e

# stop execution when error happend even inside pipeline 
set -eo pipeline

# stop when access to unknown variable 
set -u

# print each command before execution
set -x

# export source export variables
set -a
source file-with-variables.env

execute command via default editor

ctrl+x+e

edit last command via editor

fc

folder into bash script

working folder

pwd

process directory process working dir

pwdx <process id>

bash reading content of the file to command-line parameter

--extra-vars 'rpm_version=$(cat version.txt)'
--extra-vars 'rpm_version=`cat version.txt`'

all command line arguments to another program

original.sh $*

ubuntu install python

# ubuntu 18 python 3.8
sudo apt install python3.8
sudo rm /usr/bin/python3
sudo ln -s /usr/bin/python3.8 /usr/bin/python3
python3 --version
python3 -m pip install --upgrade pip

auto execute during startup, run during restart, autoexec.bat, startup script run

cron startup run

@reboot

rc0...rc1 - runlevels of linux

ID	Name	Description
0.	Halt	Shuts down the system.
1.	Single-user Mode	Mode for administrative tasks.
2.	Multi-user Mode	Does not configure network interfaces and does not export networks services.
3.	Multi-user Mode with Networking	Starts the system normally.
4.	Not used/User-definable	For special purposes.
5.	Start the system normally with with GUI	As runlevel 3 + display manager.
6.	Reboot	Reboots the system.

one of folder: /etc/rc1.d ( rc2.d ... )
contains links to /etc/init.d/S10nameofscript ( for start and K10nameofscript for shutdown ) can understand next options: start, stop, restart

/etc/init.d/apple-keyboard

#!/bin/sh
# Apple keyboard init
#
### BEGIN INIT INFO
# Provides:        cherkashyn
# Required-Start:  $local_fs $remote_fs
# Required-Stop:   $local_fs $remote_fs
# Default-Start:   4 5
# Default-Stop:
# Short-Description: apple keyboard Fn activating
### END INIT INFO

# Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting script blah "
    ;;
  stop)
    echo "Stopping script blah"
    ;;
  *)
    echo "Usage: /etc/init.d/blah {start|stop}"
    exit 1
    ;;
esac
exit 0

sudo update-rc.d apple-keyboard defaults
# sudo update-rc.d apple-keyboard remove
find /etc/rc?.d/ | grep apple | xargs ls -l

custom service, service destination

sudo vim /etc/systemd/system/YOUR_SERVICE_NAME.service

Description=GIVE_YOUR_SERVICE_A_DESCRIPTION

Wants=network.target
After=syslog.target network-online.target

[Service]
Type=simple
ExecStart=YOUR_COMMAND_HERE
Restart=on-failure
RestartSec=10
KillMode=process

[Install]
WantedBy=multi-user.target

ngrok

Description=GIVE_YOUR_SERVICE_A_DESCRIPTION

Wants=network.target
After=syslog.target network-online.target

[Service]
User=my_own_user
Group=my_own_user
Type=simple
ExecStart=/snap/ngrok/53/ngrok --authtoken aaabbbcccddd  tcp 22
Restart=on-failure
RestartSec=10
KillMode=process

[Install]
WantedBy=multi-user.target

service with docker container, service dockerized app

[Unit]
Description=Python app 
After=docker.service
Requires=docker.service

[Service]
TimeoutStartSec=5
Restart=always
ExecStartPre=-/usr/bin/docker stop app
ExecStartPre=-/usr/bin/docker rm app
ExecStart=/usr/bin/docker run \
    --env-file /home/user/.env.app \
    --name app \
    --publish 5001:5001 \
    appauth
ExecStop=/usr/bin/docker stop app

[Install]
WantedBy=multi-user.target

managing services

# alternative of chkconfig
# alternative of sysv-rc-conf

# list all services, service list 
systemctl --all
systemctl list-units --type=service --all

# in case of any changes in service file 
systemctl enable YOUR_SERVICE_NAME

systemctl start YOUR_SERVICE_NAME
systemctl status YOUR_SERVICE_NAME
systemctl daemon-reload YOUR_SERVICE_NAME
systemctl stop YOUR_SERVICE_NAME

reset X-server, re-start xserver, reset linux gui ubuntu only

Ctrl-Alt-F1

sudo init 3
sudo init 5

sudo pkill X

sudo service lightdm stop
sudo service lightdm force-reload

start

sudo startx

sudo service lightdm start

xbind catch shortcuts, custom shortcuts

doesn't work with "super"/"win" button should be activated in "startup"/service

# "echo 'pressed' > ~/out.txt"
# "xdotool getactivewindow key ctrl+c"
xte 'keydown Control_L' 'key c' 'keyup Control_L'
    release + Control_L + c

xbindkeys --key

xserver automation

keymap

apt-get install xdotool
xdotool windowactivate $each_window 
xdotool key --window $each_window Return alt+f e Down Down Return

linux x-server automation

sudo apt install xautomation
# emulate key Super+L
xte 'keydown Super_L' 'key l' 'keyup Super_L'

find all symlinks

ls -lR . | grep ^l

grep asterix, grep between

cat secrets | grep ".*Name.*Avvo.*"

grep exclude grep skip folder grep folder

grep -ir --exclude-dir=node_modules "getServerSideProps"
grep -r --files-with-matches --exclude-dir={ad-frontend,data-portal}  "\"index\""

grep multi folders

grep -ir "getServerSideProps" /home/folder1 /home/folder2

full path to file, file behind symlink, absolute path to file

readlink -f {file}
readlink -f `dirname $0`
realpath {file}

or

python -c 'import os.path; print(os.path.realpath("symlinkName"))'

filename from path

basename {file}

folder name from path, folder of file, file directory, file folder, parent folder, parent dir

dirname {file}
nautilus "$(dirname -- "$PATH_TO_SVG_CONFLUENCE")"

print full path to files inside folder, check folder for existence path check for existence

ls -d <path to folder>/*

for each_path in `find /mapr/dp.ch/vantage/data/collected/MDF4/complete -maxdepth 5`; do    
    if [ -d "$each_path" ]; 
    then
        echo "exists: $each_path"
    else
        echo "not a path: $each_path"        
    fi
done

ls directory, ls current folder, ls path, ls by path

find $FOLDER -maxdepth 4 -mindepth 4 | xargs ls -lad

real path to link

readlink 'path to symlink'

where is program placed, location of executable file

which "program-name"

permission denied

# issue with permission ( usually on NFS or cluster )
# find: '/mnt/nfs/ml-training-mongodb-pvc/journal': Permission denied
# 
# solution:
sudo docker run --volume  /mnt/nfs:/nfs -it busybox /bin/sh
chmod -R +r /nfs/ml-training-mongodb-pvc/journal

find file by name find by name

locate {file name}

exclude DB

/etc/updatedb.conf

find files by mask

locate -ir "brand-reader*"
locate -b "brand-reader"

you need to update filedatabase: /var/lib/mlocate/mlocate.db

sudo updatedb

find file, search file, skip permission denied suppress permission denied find by name

find . -name "prd-ticket-1508.txt"  2>&1 | grep -v "Permission denied"
# suppress permission denied, error pipe with stderror
find /tmp -name 'labeler.jar' |& grep -v "Permission denied"

find multiply patterns

find . -name "*.j2" -o -name "*.yaml"

find file by last update time

find / -mmin 2

find with exec find md5sum

find . -exec md5sum {} \;
find . -name "*.json" | while read each_file; do cat "$each_file" > "${each_file}".txt; done

delete files that older than 5 days

find ./my_dir -mtime +5 -type f -delete
# default variable, env var default
find ${IMAGE_UPLOAD_TEMP_STORAGE:-/tmp/image_upload} -mtime +1 -type f -delete

find files/folders by name and older than 240 min

find /tmp -maxdepth 1 -name "native-platform*" -mmin +240 | xargs  --no-run-if-empty -I {} sudo rm -r {} \; >/dev/null 2>&1

find files/folders by regexp and older than 240 min, find depth, find deep

find /tmp -maxdepth 1 -mmin +240 -iname "[0-9]*\-[0-9]" | xargs -I {} sudo rm -r {} \; >/dev/null 2>&1

find large files, find big files

find . -type f -size +50000k -exec ls -lh {} \;
find . -type f -size +50000k -exec ls -lh {} \; | awk '{ print $9 ": " $5 }'

find files on special level, find on level

find . -maxdepth 5 -mindepth 5

find by mask find

find /mapr/vantage/data/store/processed/*/*/*/*/*/Metadata/file_info.json

find with excluding folders, find exclude

find . -type d -name "dist" ! -path  "*/node_modules/*"

find function declaration, print function, show function

type <function name>
declare -f <function name>

builtin, overwrite command, rewrite command

cd()
{
   # builtin going to execute not current, but genuine function
   builtin cd /home/projects
}

folder size, dir size, directory size, size directory, size folder size of folder, size of directory

sudo du -shc ./*
sudo du -shc ./* | sort -rh | head -5

free space, space size, dir size, no space left

df -ha
df -hT /
du -shx /* | sort -h

# size of folder
du -sh /home

# size my sub-folders
du -mh /home

# print first 5 leaders of size-consumers
# slow way: du -a /home | sort -n -r | head -n 5
sudo du -shc ./* | sort -rh | head -5

du -ch /home
# find only files with biggest size ( top 5 )
find -type f -exec du -Sh {} + | sort -rh | head -n 5

yum ( app search )

yum list {pattern}

( example: yum list python33 )

yum install {package name}
yum repolist all
yum info {package name}
yumdb info {package name}

rpm (http://ftp.rpm.org/max-rpm/ch-rpm-query.html)

print all packages and sort according last updated on top

rpm -qa --last

information about package ( help page, how to execute ... )

rpm -qai

information about package with configuration

rpm -qaic
rpm -qi wd-tomcat8-app-brandserver

install without sudo rpm without sudo

rpm -ivh --prefix=$HOME browsh_1.6.4_linux_amd64.rpm

jobs

fg, bg, jobs

stop process and start it into background

ctrl-Z
bg

stop process and resume it, disconnect from process and leave it running

ctrl-Z
fg

resume process by number into list 'jobs'

fg 2

shell replacing, redirect output to file, fork new process start

bash
exec > output-file.txt
date
# the same as 'exit'
exec <&-
cat output-file.txt

output to file with variable, output to variable

gen_version="5.2.1"
$(find /mapr/dp.prod/vantage/data/processed/gen/$gen_version/ -maxdepth 5 -mindepth 5 | awk -F '/' '{print $14}' > gt-$gen_version.list)

execute command and exit

bash
exec ls -la

execute command from string, execute string, run string

echo "ls" | xargs -i sh -c "{}"

xargs with multiple arguments

find . | xargs -I % sh -c 'md5sum %; ls -la %;'

run naked terminal without bashrc

bash --norc

capture terminal output to file, save output of the commands to file

script output-file-name.txt

{my commands }

exit
cat output-file-name.txt

disconnect from terminal and let command be runned

ctrl-Z
disown -a && exit

postponed execution, execute command by timer, execute command from now, timer command

for graphical applications DISPLAY must be specified

using built-in editor

at now + 5 minutes
at> DISPLAY=:0 rifle /path/to/image
^D

using inline execution

echo "DISPLAY=:0 rifle /path/to/image/task.png" | at now + 1 min
echo "DISPLAY=:0 rifle /path/to/image/task.png" | at 11:01

print all files that process is reading

strace -e open,access <command to run application>

find process by name

ps fC firefox
pgrep firefox

pid of process by name

pidof <app name>
pidof chrome

process by id

ll /proc/${process_id}
# process command line
cat /proc/${process_id}/cmdline

current process id parent process id

echo $$
echo ${PPID}

process list, process tree

# process list with hierarchy 
ps axjf
ps -ef --forest
ps -fauxw

# process list full command line, ps full cmd
ps -ef ww 

# list of processes by user
ps -ef -u my_special_user

process list without ps

links to processes

ls -l /proc/*/exe
ls -l /proc/*/cwd
cat /proc/*/cmdline

process full command, ps full, ps truncate

ps -ewwo pid,cmd

threads in process

ps -eww H -p $PROCESS_ID

windows analogue of 'ps aux'

wmic path win32_process get Caption, Processid, Commandline

kill -3

output to log stop process

remove except one file

rm -rf  -- !(exclude-filename.sh)

cron

You have to escape the % signs with % where is file located

sudo less /var/spool/cron/crontabs/$USER

cron activating

sudo service cron status

all symbols '%' must be converted to '%'

# edit file 
# !!! last line should be empty !!!
crontab -e
# list of all jobs
crontab -l

adding file with cron job

echo " * * * * echo `date` >> /out.txt" >> print-date.cron
chmod +x print-date.cron
crontab print-date.cron

example of cron job with special parameters

HOME=/home/ubuntu
0 */6 * * * /home/ubuntu/list-comparator-W3650915.sh >/dev/null 2>&1
9 */6 * * * /home/ubuntu/list-comparator-W3653989.sh >/dev/null 2>&1
# each 6 hours in specific hour
25 1,7,13,19 * * * /home/ubuntu/list-comparator-W3651439.sh >/dev/null 2>&1

logs

sudo tail -f /var/log/syslog

is cron running

ps -ef | grep cron | grep -v grep

start/stop/restart cron

systemctl start cron
systemctl stop cron
systemctl restart cron

skip first line, pipe skip line

# skip first line in output
docker ps -a | awk '{print $1}' | tail -n +2

error to null

./hbase.sh 2>/dev/null

stderr to stdout, error to out

sudo python3 echo.py > out.txt 2>&1 &
sudo python3 echo.py &> out.txt &
sudo python3 echo.py > out.txt &

grep with line number

grep -nr "text for search" .

grep only in certain folder without recursion, grep current folder, grep in current dir

# need to set * or mask for files in folder !!!
grep -s "search_string" /path/to/folder/*
sed -n 's/^search_string//p' /path/to/folder/*

# grep in current folder
grep -s "search-string" * .*

grep before

grep -B 4
grep --before 4

grep after

grep -A 4
grep --after 4

grep regexp

printf "# todo\n## one\n### description for one\n## two\n## three" | grep "[#]\{3\}"
# printf is sensitive to --- strings
### grep boundary between two numbers
printf "# todo\n## one\n### description for one\n## two\n## three" | grep "[#]\{2,3\}"
printf "# todo\n## one\n### description for one\n## two\n## three" | grep --extended-regexp "[#]{3}"
### grep regexp 
## characters
# [[:alnum:]]	All letters and numbers.	"[0-9a-zA-Z]"
# [[:alpha:]]	All letters.	                "[a-zA-Z]"
# [[:blank:]]	Spaces and tabs.         	[CTRL+V<TAB> ]
# [[:digit:]]	Digits 0 to 9.	                [0-9]
# [[:lower:]]	Lowercase letters.	        [a-z]
# [[:punct:]]	Punctuation and other characters.	"[^a-zA-Z0-9]"
# [[:upper:]]	Uppercase letters.	        [A-Z]
# [[:xdigit:]]	Hexadecimal digits.	        "[0-9a-fA-F]"
	
## quantifiers
# *	Zero or more matches.
# ?	Zero or one match.
# +	One or more matches.
# {n}	n matches.
# {n,}	n or more matches.
# {,m}	Up to m matches.
# {n,m}	From n up to m matches.
du -ah .  | sort -r | grep -E "^[0-9]{2,}M"

grep between, print between lines

oc describe pod/gateway-486-bawfps | awk '/Environment:/,/Mounts:/'

grep text into files

grep -rn '.' -e '@Table'
grep -ilR "@Table" .

grep OR operation

cat file.txt | grep -e "occurence1" -e "occurence2"
cat file.txt | grep -e "occurence1\|occurence2"

grep AND operation

cat file.txt | grep -e "occurence1.*occurence2"

grep not included, grep NOT

cat file.txt | grep -v "not-include-string"
cat file.txt | grep -v -e "not-include-string" -e "not-include-another"

grep with file mask

grep -ir "memory" --include="*.scala"

grep with regexp, grep regexp

grep -ir --include=README.md ".*base" 2>/dev/null

echo "BN_FASDLT/1/20200624T083332_20200624T083350_715488_BM60404_BN_FASDLT.MF4" | awk -F "/" '{print $NF}' | grep "[0-9]\{8\}"

echo "185.43.224.157" | grep '^[0-9]\{1,3\}\.'
echo "185.43.224.157" | egrep '^[0-9]{1,3}\.'
echo "185.43.224.157" | egrep '^[0-9][0-9]+[0-9]+\.'

grep with filename

grep  -rH -A 2 "@angular/core"

grep without permission denied

grep -ir --include=README.md "base" 2>/dev/null

grep filename, grep name

grep -lir 'password'

inner join for two files, compare string from different files

grep -F -x -f path-to-file1 path-to-file2
grep --fixed-strings --line-regexp -f path-to-file1 path-to-file2

difference between two files without spaces

diff -w file1.txt file2.txt

show difference in lines with context

diff -c file1.txt file2.txt

show equal lines ( reverse diff )

fgrep -xf W3651292.sh W3659261.sh

show difference between two dates, date difference, time difference

apt install dateutils
dateutils.ddiff -i '%Y%m%d%H%M%S' -f '%y %m %d %H %M %S' 20160312000101 20170817040001

adjust time, adjust clock, sync clock, computer clock

/etc/systemd/timesyncd.conf.d/90-time-sync.conf

[Time]
NTP=ntp.ubuntu.com
FallbackNTP=ntp.ubuntu.com

restart time sync service

timedatectl set-ntp true && systemctl restart systemd-timesyncd.service

replace character into string

array = echo $result | tr {}, ' '

change case of chars ( upper, lower )

echo "hello World" | tr '[:lower:]' '[:upper:]

replace all chars

echo "hello World 1234 woww" | tr -dc 'a-zA-Z'

replace text in all files of current directory, replace inline, replace inplace, inline replace, sed inplace

sed --in-place 's/LinkedIn/Yahoo/g' *
# replace tab symbol with comma symbol
sed --in-place 's/\t/,/g' one_file.txt

# in case of error like: couldn't edit ... not a regular file
grep -l -r "LinkedIn" | xargs sed --in-place s/LinkedIn/Yahoo/g

# sed for folder sed directory sed for files
find . -type f -exec sed -i 's/import com.fasterxml.jackson.module.scala.DefaultScalaModule;//p' {} +

no editor replacement, no vi no vim no nano, add line without editor, edit property without editor

# going to add new line in property file without editor
sed --in-place 's/\[General\]/\[General\]\nenable_trusted_host_check=0/g' matomo-php.ini

timezone

timedatectl | grep "Time zone"
cat /etc/timezone

date formatting, datetime formatting, timestamp file, file with timestamp

# print current date
date +%H:%M:%S:%s
# print date with timestamp
date -d @1552208500 +"%Y%m%dT%H%M%S"
date +%Y-%m-%d-%H:%M:%S:%s
# output file with currenttime file with currenttimestamp
python3 /imap-message-reader.py > message_reader`date +%H:%M:%S`.txt

timestamp to T-date

function timestamp2date(){
    date -d @$(( $1/1000000000 )) +"%Y%m%dT%H%M%S"
}
timestamp2date 1649162083168929800

generate random string

openssl rand -hex 30
# or 
urandom | tr -dc 'a-zA-Z0-9' | fold -w 8 | tr '[:upper:]' '[:lower:]' | head -n 1

find inside zip file(s), grep zip, zip grep

zgrep "message_gateway_integration" /var/lib/brand-server/cache/zip/*.zip

grep zip, find inside zip, inside specific file line of text

ls -1 *.zip | xargs -I{} unzip -p {} brand.xml  | grep instant-limit | grep "\\."

unzip into specific folder

unzip file.zip -d output_folder

unzip without asking for action

unzip -o file.zip -d output_folder

unzip one file

unzip -l $ARCHIVE_NAME
unzip $ARCHIVE_NAME path/to/file/inside

7zip

sudo apt install p7zip-full

7za l archive.7z
7za x archive.7z

tar

tar archiving tar compression

# tar create
tar -cf jdk.tar 8.0.265.j9-adpt
# tar compression
tar -czvf jdk.tar.gz 8.0.265.j9-adpt

untar

# tar list of files inside
tar -tf jdk.tar

# tar extract untar
tar -xvf jdk.tar -C /tmp/jdk
# extract into destination with removing first two folders
tar -xvf jdk.tar -C /tmp/jdk --strip-components=2
# extract from URL untar from url
wget -qO- https://nodejs.org/dist/v10.16.3/node-v10.16.3-linux-x64.tar.xz | tar xvz - -C /target/directory

pipeline chain 'to file'

echo "hello from someone" | tee --append out.txt
echo "hello from someone" | tee --append out.txt > /dev/null

vi

vi wrap( :set wrap, :set nowrap )

shortcut	description
/	search forward
?	search backward
n	next occurence
N	prev occurence

command prompt change console prompt console invitation

.bashrc of ubuntu

export PS1="my_host $(date +%d%m_%H%M%S)>"

if [ "$color_prompt" = yes ]; then
#    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@$(date +%d%m_%H%M)\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '

else
#    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
    PS1='${debian_chroot:+($debian_chroot)}\u:\$(date +%d.%m_%H:%M)\w\$ '

fi
unset color_prompt force_color_prompt

export PROMPT_COMMAND="echo -n \[\$(date +%H:%M:%S)\]\ "

command line color prompt color console

# green
export PS1=`printf "\033[31m$ staging \033[39m"`
# red
export PS1=`printf "\033[32m$ staging \033[39m"`

Color	Foreground	Background
Black	\033[30m	\033[40m
Red	\033[31m	\033[41m
Green	\033[32m	\033[42m
Orange	\033[33m	\033[43m
Blue	\033[34m	\033[44m
Magenta	\033[35m	\033[45m
Cyan	\033[36m	\033[46m
Light gray	\033[37m	\033[47m
Fallback to distro's default	\033[39m	\033[49m

last executed exit code

echo $?

memory dump

cat /proc/meminfo

memory limit memory usage

cat /sys/fs/cgroup/memory/memory.limit_in_bytes
cat /sys/fs/cgroup/memory/memory.usage_in_bytes

max open files

cat /proc/sys/fs/file-max

open file by type, open image

mimetype -d {filename}
xdg-open {filename}
w3m {filename}

open in browser, open url

sensible-browser http://localhost:3000/api/status
x-www-browser http://localhost:3000/api/status
# for MacOS
open http://localhost:3000/api/status

wget post

wget --method=POST http://{host}:9000/published/resources/10050001.zip

wget to console

wget -O- http://{host}:8500/wd-only/getBrandXml.jsp?brand=229099017 > /dev/null  2>&1

wget to console without additional info

wget -nv -O- http://{host}:8500/wd-only/getBrandXml.jsp?brand=229099017 2>/dev/null

wget to specific file, download file to specific file

wget -O out.zip http://{host}:9000/published/resources/10050001.zip
# in case of complex output path
curl -s http://{host}:9000/published/resources/10050001.zip --create-dirs -o /home/path/to/folder/file.zip

wget to specific folder

wget http://host:9090/wd-only/1005000.zip --directory-prefix="/home/temp/out"

wget https without checking certificate

wget --no-check-certificate https://musan999999.mueq.adas.intel.com:8888/data-api/session/

wget with user wget with credentials

wget --user $ARTIFACTORY_USER --password $ARTIFACTORY_PASS $ARTIFACTORY_URL

wget with specific timeout

wget --tries=1 --timeout=5 --no-check-certificate https://musan999999.mueq.adas.intel.com:8888/data-api/session/

wget proxy, wget via proxy

wget -e use_proxy=yes -e http_proxy=127.0.0.1:7777 https://mail.ubsgroup.net/

or just with settings file "~/.wgetrc"

use_proxy = on
http_proxy =  http://username:password@proxy.server.address:port/
https_proxy =  http://username:password@proxy.server.address:port/
ftp_proxy =  http://username:password@proxy.server.address:port/

or via socks5

all_proxy=socks5://proxy_host:proxy_port wget https://mail.ubsgroup.net

zip files, zip all files

zip -r bcm-1003.zip *

zip file with password zip protect with password

zip --encrypt 1.zip 1.html

zip file without saving path, zip path cleanup

zip --junk_paths bcm-1003.zip *

encrypt decrypt

sudo apt install ccrypt
# encrypt file
ccencrypt file1.txt
# ccencrypt file1.txt --key mysecretkey
# print decrypted content
ccat file1.txt.cpt
# decrypt file
ccdecrypt file1.txt.cpt
# ccdecrypt file1.txt.cpt --key mysecretkey
# try to guess password
# ccguess file1.txt.xpt

using parameters for aliases

alias sublime_editor=/Applications/SublimeEditor/Sublime

subl(){
  sublime_editor "$1" &
}

print alias, print function

alias sublime_editor
type subl

sed cheat sheet, sed replace

replace "name" with "nomen" string
sed 's/name/nomen/g'

# replace only second occurence
# echo "there is a test is not a sentence" | sed 's/is/are/2'

example of replacing all occurences in multiply files

for each_file in `find -iname "*.java"`; do
	sed --in-place 's/vodkafone/cherkavi/g' $each_file
done

sed add prefix add suffix replace in line multiple commands

echo "aaaa find_string bbbb " | sed 's/find_string/replace_to/g' | sed 's/"//g; s/$/\/suffix/; s/^/\/prefix/'

sed remove sed delete

# remove line with occurence
sed --in-place '/.*jackson\-annotations/d' $each_file

print line by number from output, line from pipeline, print one line from file

locate -ir "/zip$" | sed -n '2p'
cat out.txt | sed -n '96p'

issue with windows/unix carriage return

/usr/bin/bash^M: bad interpreter: No such file or directory

solution

sed -i -e 's/\r$//' Archi-Ubuntu.sh

calculate amount of strings

ps -aux | awk 'BEGIN{a=0}{a=a+1}END{print a}'

boolean value

true
false

last changed files, last updated file

find -cmin -2

temp file temporary file create temp file

mktemp

cURL command

curl without password

~/.netrc

machine my-secret-host.com login my-secret-login password my-secret-password
machine my-secret-host2.com login my-secret-login2 password my-secret-password2

curl --netrc --request GET my-secret-host.com/storage/credentials

return code 0 if 200, curl return code

curl --fail --request GET 'https://postman-echo.com/get?foo1=bar1&foo2=bar2'

curl with authentication

curl --request POST \
--data "client_id=myClient" \
--data "grant_type=client_credentials" \
--data "scope=write" \
--data "response_type=token" \
--cert "myClientCertificate.pem" \
--key "myClientCertificate.key.pem" \
"https://openam.example.com:8443/openam/oauth2/realms/root/access_token"
{
  "access_token": "sbQZ....",
  "scope": "write",
  "token_type": "Bearer",
  "expires_in": 3600
}
	
### echo server mock server 
```sh
curl --location --request GET 'https://postman-echo.com/get?foo1=bar1&foo2=bar2'

curl username, curl with user and password, curl credentials

curl -u username:password http://example.com
# basic authentication
echo -n "${username}:${password}" | base64
curl -v --insecure -X GET "https://codebeamer.ubsgroup.net:8443/cb/api/v3/wikipages/21313" -H "accept: application/json" -H "Authorization: Basic "`echo -n $TSS_USER:$TSS_PASSWORD | base64`

# bearer authentication
curl --insecure --location --oauth2-bearer $KEYCLOAK_TOKEN "https://portal.apps.devops.vantage.org/session-lister/v1/sessions/cc17d9f8-0f96-43e0-a0dc-xxxxxxx"

# or with certificate 
curl  --cacert /opt/CA.cer --location --oauth2-bearer $KEYCLOAK_TOKEN "https://portal.apps.devops.vantage.org/session-lister/v1/sessions/cc17d9f8-0f96-43e0-a0dc-xxxxxxx"

curl head

curl --head http://example.com

curl redirect, redirect curl, curl 302

curl -L http://example.com

curl PUT example with file

curl -X PUT --header "Content-Type: application/vnd.wirecard.brand.apis-v1+json;charset=ISO-8859-1" -H "x-username: cherkavi" -d@put-request.data http://q-brands-app01.wirecard.sys:9000/draft/brands/229099017/model/country-configurations

curl POST example POST request

curl -X POST http://localhost:8983/solr/collection1/update?commit=true \
-H "Content-Type: application/json" --data '{"add":"data"}'

curl -X POST http://localhost:8983/solr/collection1/update?commit=true \
-H "Content-Type: application/json" --data-raw '{"add":"data"}'

curl -X POST http://localhost:8983/solr/collection1/update?commit=true \
-H "Content-Type: application/json" --data-binary '{"add":"data"}'

# encoding special symbols curl special symbols
curl -X POST http://localhost:8983/solr/collection1/update?commit=true \
-H "Content-Type: application/json" --data-urlencode '{"add":"Tom&Jerry"}'

# or with bash variable
SOME_DATA="my_personal_value"
curl -X POST http://localhost:8983/solr/collection1/update?commit=true -H "Content-Type: application/json" --data-binary '{"add":"'$SOME_DATA'"}'

# or with data from file
curl -X POST http://localhost:8983/test -H "Content-Type: application/json" --data-binary '@/path/to/file.json'

# or with multipart body
curl -i -X POST -H "Content-Type: multipart/form-data" -F "data=@test.mp3" -F "userid=1234" http://mysuperserver/media/upload/

# multiline body
curl -X 'POST' $SOME_HOST \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "bdcTimestamp": 6797571559111,
  "comment": "Some comment",
  "loggerTimestamp": 1623247031477189001,
  }'

# curl with inline data curl here document curl port document here pipe
json_mappings=`cat some_file.json`
response=`curl -X POST $SOME_HOST -H 'Content-Type: application/json' \
-d @- << EOF
{
	"mappings": $json_mappings,
	"settings" : {
        "index" : {
            "number_of_shards" : 1,
            "number_of_replicas" : 0
        }
    }
}
EOF
`
echo $response

# POST request GET style
curl -X POST "http://localhost:8888/api/v1/notification/subscribe?email=one%40mail.ru&country=2&state=517&city=qWkbs&articles=true&questions=true&listings=true" -H "accept: application/json"

curl escape, curl special symbols

# https://kb.objectrocket.com/elasticsearch/elasticsearch-cheatsheet-of-the-most-important-curl-requests-252
curl -X GET "https://elasticsearch-label-search-prod.vantage.org/autolabel/_search?size=100&q=moto:*&pretty"

escape single quotas

echo "'" 'sentence' "'"

curl without progress, curl silent

curl -s -X GET http://google.com
curl --silent -X GET http://google.com
curl http://google.com 2>/dev/null

curl certificate skipping, curl ssl, curl https, curl skip ssl

curl --insecure -s -X GET http://google.com

curl with additional output, curl verbosive mode

curl --verbose --insecure -s -X GET http://google.com

curl cookie, curl header cookie

chrome extension cookies.txt

# send predefined cookie to url
curl -b path-to-cookie-file.txt -X GET url.com

# send cookie from command line
curl --cookie "first_cookie=123;second_cookie=456;third_cookie=789" -X GET url.com

# send cookie from command line 
curl 'http://localhost:8000/members/json-api/auth/user' -H 'Cookie: PHPSESSID=5c5dddcd96b9f2f41c2d2f87e799feac'

# collect cookie from remote url and save in file
curl -c cookie-from-url-com.txt -X GET url.com

curl binary

python3 ${HOME_PROJECTS_GITHUB}/python-utilities/html-scraping/binary-html/beautifulsoup.py https://amazon.de

string encoding for http

sudo apt install gridsite-clients
urlencode "- - -"

curl with encoding to another codepage, from win1251 to utf8

curl "http://some.resource/read_book.php?id=66258&p=1" | iconv --from-code WINDOWS-1251 --to-code UTF-8

curl with parsing, curl part of the page

curl status code, curl response code, curl duration

airflow_trigger(){
  SESSION_ID=$1
  ENDPOINT=$2
  BODY='{"conf":{"session_id":"'$SESSION_ID'","branch":"merge_labels"}}'
  curl --silent -w "response-code: %{http_code}\n   time: %{time_starttransfer}" --data-binary $BODY -u $AIRFLOW_USER:$AIRFLOW_PASSWORD -X POST $ENDPOINT
  return $?
}
DAG_NAME='labeling'
airflow_trigger $each_session "https://airflow.vantage.org/api/experimental/dags/$DAG_NAME/dag_runs"

curl --show-error "http://some.resource/read_book.php?id=66258&p=1"

curl execution time

curl --max-time 10 -so /dev/null -w '%{time_total}\n' google.com

curl script curl replacement

curl "https://{foo,bar}.com/file_[1-4].webp" --output "#1_#2.webp"

json parser output to json pipe json

# installation 
pip3 install jc
apt-get install jc

# parse general output to json
jc --pretty ls -la
# using predefined parser
dig www.google.com | jc --dig --pretty

json xml sql yaml converter

spyql doc
https://danielcmoura.com/blog/2022/spyql-cell-towers/

echo '{"a": 10, "b": "kitchen"}' | spyql -Otable=my_table "SELECT  json.a as indicator_value, json.b as place FROM json TO sql"

jq json navigator json parser json parsing parse json parsing json json processing json query

json query doc
json tool json walk json analyzer

snap install fx
jq playground
WARNING: jq round up big numbers ( for version <=1.6 ), use use 1.7+ instead sudo mv /usr/bin/jq-linux-amd64 /usr/bin/jq:

echo '{"loggerTimestamp": 1657094097468421888}' | jq .
# {
#  "loggerTimestamp": 1657094097468422000
# }

jq is not working properly with "-" character in property name !!!
jq is not working sometimes with "jq any properties", need to split them to two commands

docker network inspect mysql_web_default | jq '.[0].Containers' | jq .[].Name

echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | \
jq ".[] | .name"

# json output pretty print, json pretty print, json sort
echo output.json | jq .
# sort by keys
echo output.json | jq -S .

# jq select with condition
jq -e 'select(.[].name == "CP_END")' $SESSION_METADATA_FOLDER/$SESSION_ID
echo $? # return 0 only when met the condition, otherwise - 1

# .repositories[].repositoryName
aws ecr describe-repositories | jq '.repositories[] | select(.repositoryName == "cherkavi-udacity-github-action-fe")'

# jq filter by condition
docker network inspect mysql_web_default | jq '.[0].Containers' | jq '.[] | select(.Name=="web_mysql_ui")' | jq .IPv4Address

# jq create another document filter json transform json
echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | jq '[.[] | {id, name} ]'
echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | jq '[.[] | {number:.id, warrior:.name} ]'
	
# jq convert to csv
echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | \
jq '.[] | if .name == "Richard" then . else empty end | [.id, .name] | @csv'

# jq as a table
echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | jq -r '["ID","NAME"], ["--","------"], (.[] | [.id,.name]) | @tsv' 
	
# jq get first element
echo '[{"id": 1, "name": "Arthur", "age": "21"},{"id": 2, "name": "Richard", "age": "32"}]' | jq '.[0] | [.name, .age] | @csv'

# convert from yaml to json, retrieve values from json, convert to csv
cat temp-pod.yaml | jq -r -j --prettyPrint | jq '[.metadata.namespace, .metadata.name, .spec.template.spec.nodeSelector."kubernetes.io/hostname"] | @csv'

# multiply properties from sub-element
aws s3api list-object-versions --bucket $AWS_S3_BUCKET_NAME --prefix $AWS_FILE_KEY | jq '.Versions[] | [.Key,.VersionId]'

echo '{"smart_collections":[{"id":270378401973},{"id":270378369205}]}' | jq '. "smart_collections" | .[] | .id'

jq 'if .attributes[].attribute == "category" and (.attributes[].normalizedValues != null) and (.attributes[].normalizedValues | length )>1 then . else empty end'
	
# jq remove quotas raw text
jq -r ".DistributionList.Items[].Id"

# jq escape symbols
kubectl get nodes -o json | jq -r '.items[].metadata.annotations."alpha.kubernetes.io/provided-node-ip"'

# edit variables inside JSON file
ENV_DATA=abcde
jq --arg var_a "$ENV_DATA" '.ETag = $var_a' cloud_front.json
jq '.Distribution.DistributionConfig.Enabled = false' cloud_front.json

json compare json diff

cmp <(jq -cS . A.json) <(jq -cS . B.json)
diff <(jq --sort-keys . A.json) <(jq --sort-keys . B.json)

json deep compare

# export JSON_COMPARE_SUPPRESS_OUTPUT=""
export JSON_COMPARE_SUPPRESS_OUTPUT="true"
python3 jsoncompare.py  $FOLDER_CSV/$SESSION_ID $FOLDER/$SESSION_ID

parsing yaml, yaml processing yaml query

yaml tool edit yaml xpath

pip install yamlpath

yaml get value by xpath

echo '
first: 
  f_second: one_one
second: 2
' | yaml-get -p first.f_second
# one_one

yaml search for xpath, print files with values in xpath

echo '
first: 
  f_second: one_one
second: 2
' | yaml-paths --search=%one

yaml edit by xpath ( scalars only )

echo '
first: one
second: 2 
' | yaml-set -g first --value=1
# ---
# first: 1
# second: 2

yaml difference between two yaml files

echo '
second: 2
first: 
  f_second: one_one
' > temp_1.yaml
echo '
first: 
  f_second: one_two
second: 2
' > temp_2.yaml
yaml-diff temp_1.yaml temp_2.yaml
# < "one_one"
# ---
# > "one_two"

yq doc

yq examples

# read value
cat k8s-pod.yaml | yq r - --printMode pv  "metadata.name"

# convert to JSON
cat k8s-pod.yaml | yq - r -j --prettyPrint
# convert yaml to json|props|xml|tsv|csv
cat k8s-pod.yaml | yq --output-format json

# yaml remove elements clear ocp fields
yq 'del(.metadata.managedFields,.status,.metadata.uid,.metadata.resourceVersion,.metadata.creationTimestamp,.spec.clusterIP,.spec.clusterIP)' service-data-api-mdf4download-service.yaml

# yaml editor 
yq 'del(.metadata.managedFields,.status,.metadata.uid,.metadata.resourceVersion,.metadata.creationTimestamp,.spec.clusterIP,.spec.clusterIP),(.metadata.namespace="ttt")' service-data-api-mdf4download-service.yaml

yq converter

# convert yaml to json|props|xml|tsv|csv
cat file.yaml | yq --output-format json

parsing xml parsing xml processing

xq

# installation
pip3 install xq
# xq usage ??? is it not working as expected ????

parse xml with xpath

# installation
sudo apt install libxml-xpath-perl
# parse xml from stdin
curl -s https://www.w3schools.com/xml/note.xml | xpath -e '/note/to | /note/from'
curl -s https://www.w3schools.com/xml/note.xml | xpath -e '/note/to/text()'

parse xml with xmllint

# installation
sudo apt  install libxml2-utils

## usage
TEMP_FILE=$(mktemp)
curl -s https://www.w3schools.com/xml/note.xml > $TEMP_FILE
xmllint --xpath '//note/from' $TEMP_FILE
xmllint --xpath 'string(//note/to)' $TEMP_FILE
xmllint --xpath '//note/to/text()' $TEMP_FILE

# avoid xmllint namespace check
xmllint --xpath "//*[local-name()='project']/*[local-name()='modules']/*[local-name()='module']/text()" pom.xml
# avoid issue with xmllint namespace
cat pom.xml | sed '2 s/xmlns=".*"//g' | xmllint --xpath "/project/modules/module/text()" -

# debug xml xpath debug 
xmllint --shell  $TEMP_FILE
rm $TEMP_FILE

xml pretty print, xml format

xmllint --format /path/to/file.xml > /path/to/file-formatted.xml

xml validation

xmllint --noout file.xml; echo $?

html prettifier

cat index.html | grep tidy

parse html parsing

# sudo apt install libxml-xpath-perl
xpath -e $path $filename

# Parse HTML and extract specific elements
xmllint --html --xpath  $path $filename

html parsing html processing html query, hq tool hq installation

pip install hq

# or https://pypi.org/project/hq/0.0.4/#files
# sudo python3 setup.py install

hq usage

curl https://www.w3schools.com/xml | hq '`title: ${/head/title}`'
cat index.html | hq '/html/body/table/tr/td[2]/a/text()'
# retrieve all classes
cat p1-utf8.txt | hq '/html/body/table//p/@class'
# retrieve all texts from 'p'
cat p1-utf8.txt | hq '/html/body/table//p/text()'
# retrieve all texts from 'p' with condition
cat p1-utf8.txt | hq '/html/body/table//p[@class="MsoNormal"]/text()'
# retrieve html tag table
cat p1-utf8.txt | hq '//table'

cat $filename | hq '`Hello, ${/html/head/title}!`'

# https://www.w3.org/TR/xquery-31/#id-flwor-expressions
hq -f $filename '
let $path := /html/body/ul/li[*];
for $el in $path
    let $title:=`${ $el/span/div/div/div/div[2]/div[3]/div/div[1]/div/div[1]/div[1]/h2 }`
    let $price1:=`${ $el/span/div/div/div/div[2]/div[3]/div/div[1]/div/div[1]/div[2]/div[1]/div/span/span[1] }`
    let $price2:=`${ $el/span/div/div/div/div[2]/div[3]/div/div[1]/div/div[1]/div[2]/div[2]/div/span[1]/span[1] }`

    let $price:=if ($price1) then $price1 else $price2

    return `$title | $price `'

hq -f $filename '
let $path := /html/body/div[1]/li[*];
for $el in $path
    return `${ $el/article/div[2]/div[2]/h2/a } | https://www.example.de/${ $el/a/@href }`'

python html parsers

chmod recursively

chmod -R +x <folder name>

# remove world access 
chmod -R o-rwx /opt/sm-metrics/grafana-db/data
# remove group access
chmod -R g-rwx /opt/sm-metrics/grafana-db/data
# add rw access for current user
chmod u+rw screenshot_overlayed.png

find . -iname "*.sql" -print0 | xargs -0 chmod 666

create dozen of folders using one-line command

mkdir -p some-folder/{1..10}/{one,two,three}

execute command with environment variable, new environment variable for command

ONE="this is a test"; echo $ONE

activate environment variables from file, env file, export env, export all env, all variable from file, all var export, env var file

FILE_WITH_VAR=.env.local
source $FILE_WITH_VAR
export $(cut -d= -f1 $FILE_WITH_VAR)

# if you have comments in file
source $FILE_WITH_VAR
export `cat $FILE_WITH_VAR | awk -F= '{if($1 !~ "#"){print $1}}'`

system log file

/var/log/syslog

Debian install package via proxy, apt install proxy, apt proxy, apt update proxy

sudo http_proxy='http://user:@proxy.muc:8080' apt install meld

proxy places, change proxy, update proxy, system proxy

remember about escaping bash spec chars ( $,.@.... )

.bashrc
/etc/environment
/etc/systemd/system/docker.service.d/http-proxy.conf
/etc/apt/auth.conf

Acquire::http::Proxy "http://username:password@proxyhost:port";
Acquire::https::Proxy "http://username:password@proxyhost:port";

snap

sudo snap set system proxy.http="http://user:password@proxy.zur:8080"
sudo snap set system proxy.https="http://user:password@proxy.zur:8080"

snap installation issue

# leads to error: cannot connect to the server
snap install <app>

# Unmask the snapd.service:
sudo systemctl unmask snapd.service

# Enable it:
systemctl enable snapd.service

# Start it:
systemctl start snapd.service

install version of app, install specific version, accessible application version

sudo apt list -a [name of the package]
sudo apt list -a kubeadm

install package for another architecture, install x86 on x64

dpkg --add-architecture i386
dpkg --print-architecture
dpkg --print-foreign-architectures
sudo apt-get install libglib2.0-0:i386 libgtk2.0-0:i386

installed package check package information

apt list <name of package>
apt show <name of package>

package update package mark

apt mark hold kubeadm
# install: this package is marked for installation.
# deinstall (remove): this package is marked for removal.
# purge: this package, and all its configuration files, are marked for removal.
# hold: this package cannot be installed, upgraded, removed, or purged.
# unhold: 
# auto: auto installed
# manual: manually installed

Debian update package

sudo apt-get install --only-upgrade {packagename}

Debian list of packages

sudo apt list
sudo dpkg -l

First letter	desired package state ("selection state")
u	unknown
i	install
r	remove/deinstall
p	purge (remove including config files)
h	hold

Second letter	current package state
n	not-installed
i	installed
c	config-files (only the config files are installed)
U	unpacked
F	half-configured (configuration failed for some reason)
h	half-installed (installation failed for some reason)
W	triggers-awaited (package is waiting for a trigger from another package)
t	triggers-pending (package has been triggered)

Third letter	error state (you normally shouldn't see a third letter, but a space, instead)
R	reinst-required (package broken, reinstallation required)

Debian list the versions available in your repo

sudo apt-cache madison {package name}

Debian install new version of package with specific version

sudo apt-get install {package name}={version}

Debian system cleanup

sudo apt-get clean
sudo apt-get autoremove --purge

uninstall specific app

sudo apt-get --purge remote {app name}

remove service ( kubernetes )

sudo invoke-rc.d localkube stop
sudo invoke-rc.d localkube status ( sudo service localkube status )
sudo update-rc.d -f localkube remove
sudo grep -ir /etc -e "kube"
rm -rf /etc/kubernetes
rm -rf /etc/systemd/system/localkube.service
vi /var/log/syslog

last executed code, last script return value

echo $?

remove VMWare player

sudo vmware-installer -u vmware-player

pdf watermark, merge pdf files into one

pdftk original.pdf stamp watermark.pdf output output.pdf

version of OS linux version os information distribution name OS name

lsb_release -a
cat /etc/*-release
uname -a
. /etc/os-release

cidr calculator

ip address of the site show ip address of remote host ip address

host google.com
dig mail.ru

print all networks

ip -4 a
ip -6 a

print all network interfaces all wifi devices

interfaces
ifconfig
nmcli d

print all wifi passwords

sudo cat /etc/NetworkManager/system-connections/* | grep -e ^ssid -e ^psk

switch on and off network interface

sudo ifdown lo && sudo ifup lo

restart network, switch off all interfaces

sudo service network-manager restart

vpn connection, connect to network

# status of all connections
nmcli d
nmcli connection
nmcli connection up id {name from previous command}
nmcli connection down id {name of connection}

connect to wifi

wifi_code='188790542'
point="FRITZ!Box 7400 YO"
nmcli device wifi connect  "$point" password $wifi_code
# sudo cat /etc/NetworkManager/system-connections/*

raw vpn connection

sudo openconnect --no-proxy {ip-address} --user=$VPN_USER $URL_VPN
sudo openconnect --no-cert-check --no-proxy --user=$VPN_USER ---servercert $URL_VPN
openconnect $URL_VPN --interface=vpn0 --user=$(id -un) --authgroup=YubiKey+PIN -vv --no-proxy --no-dtls

FILE_CERT_CA=WLAN_CA.crt
FILE_USER_KEY=xxx.ubs.corp.key
FILE_USER_CERT=xxx.ubs.corp.crt
URL_VPN=https://vpn.ubs.com
USER_VPN=xxxyyyzzz
sudo openconnect --no-proxy --user=$USER_VPN --authgroup='YubiKey+PIN' --cafile=$FILE_CERT_CA --sslkey=$FILE_USER_KEY --certificate=$FILE_USER_CERT $URL_VPN

openvpn vpn connection

# apt install network-manager-openvpn
sudo openvpn file_config.ovpn

# vpn-auth - text file with two lines: login and password
sudo openvpn --config 1.ovpn --auth-user-pass $DIR_PROJECT/vpn-auth.txt

debug network collaboration, ip packages

example with reading redis collaboration ( package sniffer )

sudo ngrep -W byline -d docker0 -t '' 'port 6379'

debug connection, print collaboration with remote service, sniffer

#                    1------------     2--------------------     3--------------
sudo tcpdump -nvX -v src port 6443 and src host 10.140.26.10 and dst port not 22
# and, or, not

keystore TrustStore

TrustStore holds the certificates of external systems that you trust.
So a TrustStore is a KeyStore file, that contains the public keys/certificate of external hosts that you trust.

## list of certificates inside truststore 
keytool -list -v -keystore ./src/main/resources/com/ubs/crm/data/api/rest/server/keystore_server
# maybe will ask for a password

## generating ssl key stores
keytool -genkeypair -keystore -keystore ./src/main/resources/com/ubs/crm/data/api/rest/server/keystore_server -alias serverKey -dname "CN=localhost, OU=AD, O=UBS AG, L=Zurich, ST=Bavaria, C=DE" -keyalg RSA
# enter password...

## Importing ( updating, adding ) trusted SSL certificates
keytool -import -file ~/Downloads/certificate.crt -keystore ./src/main/resources/com/ubs/crm/data/api/rest/server/keystore_server -alias my-magic-number

in other words, rsa certificate rsa from url x509 url:

Download the certificate by opening the url in the browser and downloading it there manually.
Run the following command: keytool -import -file <name-of-downloaded-certificate>.crt -alias <alias for exported file> -keystore myTrustStore

DNS

# check 
sudo resolvectl status | grep "DNS Servers"
systemd-resolve --status
systemctl status systemd-resolved

# restart
sudo systemctl restart systemd-resolved

# current dns
sudo cat /etc/resolv.conf
# resolving hostname
dig google.com

aws example, where 10.0.0.2 AWS DNS internal server sudo vim /etc/resolv.conf

# nameserver 127.0.0.53
nameserver 10.0.0.2
options edns0 trust-ad
search ec2.internal

encrypt file, decrypt file, encode/decode

gpg --symmetric {filename}
gpg --decrypt {filename}

# encrypt
# openssl [encryption type] -in [original] -out [output file]
openssl des3 -in original.txt -out original.txt.encrypted
# decrypt
# openssl [encryption type] -d -in [encrypted file] -out [original file]
openssl des3 -d -in original.txt.encrypted -out original.txt

# list of encryptors (des3):
openssl enc -list

add user into special group, add user to group

adduser {username} {destination group name}
edit file /etc/group

add :{username} to the end of line with {groupname}:x:999

create/add user, create user with admin rights

sudo useradd test

sudo useradd --create-home test --groups sudo 
# set password for new user
sudo passwd test
# set default bash shell 
chsh --shell /bin/bash tecmint

sudo for user, user sudo, temporary provide sudo

sudo adduser vitalii sudo
# close all opened sessions
# after your work done
sudo deluser vitalii sudo

admin rights for script, sudo rights for script, execute as root

sudo -E bash -c 'python3'

remove user

sudo userdel -r test

create group, assign user to group, user check group, user group user roles hadoop

sudo groupadd new_group
usermod --append --groups new_group my_user
id my_user

create folder for group, assign group to folder

chgrp new_group /path/to/folder

execute sudo with current env variables, sudo env var, sudo with proxy

sudo -E <command>

execute script with current env variables send to script

. ./airflow-get-log.sh
source ./airflow-get-log.sh
cat dag-runs-failed.id | . ./airflow-get-log.sh

print all logged in users, active users, connected users

users

who --all

send message to user, message for other users

write <username> <message>

sudo wall -n 'hello all logged in users '

print all users registered into system

cat /etc/passwd | cut --delimiter=: --fields=1

issue with ssh, ssh connection issue

when you see message:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

use this:

ssh-keygen -R <host>

or

rm ~/.ssh/known_hosts

proxy

proxy local, proxy for user /etc/profile.d/proxy.sh

export HTTP_PROXY=http://webproxy.host:3128
export http_proxy=http://webproxy.host:3128
export HTTPS_PROXY=http://webproxy.host:3128
export https_proxy=http://webproxy.host:3128
export NO_PROXY="localhost,127.0.0.1,.host,.viola.local"
export no_proxy="localhost,127.0.0.1,.host,.viola.local"

global proxy, proxy global, system proxy, proxy system /etc/apt/apt.conf

Acquire::http::proxy "http://proxy.company.com:80/";
Acquire::https::proxy "https://proxy.company.com:80/";
Acquire::ftp::proxy "ftp://proxy.company.com:80/";
Acquire::socks5::proxy "socks://127.0.0.1:1080/";

global proxy, proxy global, system proxy, proxy system /etc/environment

http_proxy=http://webproxy.host:3128
no_proxy="localhost,127.0.0.1,.host.de,.viola.local"

for application

create environment for http

sudo gedit /etc/systemd/system/{service name}.service.d/http-proxy.conf

[Service]
Environment="http_proxy=http://user:passw@webproxy.host:8080"

create environment for https

sudo gedit /etc/systemd/system/{service name}.service.d/https-proxy.conf
[Service]
Environment="https_proxy=http://user:passw@webproxy.host:8080"

service list of services

systemctl list-unit-files --type=service

restart service restart service stop service start

$ sudo systemctl daemon-reload
$ sudo systemctl restart {service name}
# or
sudo service {service name} stop
sudo service {service name} start

check service status

sudo systemctl is-active {service name}

enable automatic start disable autostart disable service

sudo systemctl enable {service name}
sudo systemctl disable {service name}

service check logs

systemctl status {service name}
journalctl -u {service name} -e
# print all units
journalctl -F _SYSTEMD_UNIT

# system log
journalctl -f -l 
# system log for app log
$ journalctl -f -l -u python -u mariadb
# system log since 300 second
$ journalctl -f -l -u httpd -u mariadb --since -300

check settings

systemctl show {service name} | grep proxy

for snapd

# export SYSTEM_EDITOR="vim"
# export SYSTEMD_EDITOR="vim"
sudo systemctl edit snapd.service
# will edit: /etc/systemd/system/snapd.service.d/override.conf

add next lines

[Service]
Environment=http_proxy=http://proxy:port
Environment=https_proxy=http://proxy:port

restart service

sudo systemctl daemon-reload
sudo systemctl restart snapd.service

snap proxy settings

sudo snap set system proxy.http="http://user:password@proxy.muc:8080"
sudo snap set system proxy.https="http://user:password@proxy.muc:8080"
export proxy_http="http://user:password@proxy.muc:8080"
export proxy_https="http://user:password@proxy.muc:8080"
sudo snap search visual

tools:

ETL
ETL
web management - atomicproject.io, cockpit
- install
- guide
- after installation
- use your own user/password

virtual machines

images
app with infrastructure

mapping keys, keymap, assign actions to key

show key codes

xmodmap -pke
# or take a look into "keycode ... " 
xev

remap key 'Druck' to 'Win'

xmodmap -e "keycode 107 = Super_L"

to reset

setxkbmap

make ctrl+alt the same as alt+ctrl, make ctrl+shift the same as shift+ctrl

keycode 50 = Shift_L NoSymbol Shift_L
keycode 62 = Shift_R NoSymbol Shift_R
keycode 37 = Control_L NoSymbol Control_L
keycode 105 = Control_R NoSymbol Control_R

keycode 64 = Alt_L Meta_L Alt_L Meta_L
keycode 108 = Alt_R Meta_R Alt_R Meta_R
keycode 37 = Control_L NoSymbol Control_L
keycode 105 = Control_R NoSymbol Control_R

save to use during each reboot

echo "keycode 107 = Super_L" >> ~/.Xmodmap
echo "xmodmap ~/.Xmodmap" >> ~/.xprofile

find key code

xev | grep keysym

key code, scan code, keyboard code

sudo evtest 
sudo evtest /dev/input/event21

remap [hjkl] to [Left, Down, Up, Right], cursor hjkl: option 1

remap [hjkl] to [Left, Down, Up, Right], cursor hjkl: option 2

mapping list
for using in VisualCode like environment: GTK_IM_MODULE="xim" code $* content of $HOME/.config/xmodmap-hjkl

keycode 66 = Mode_switch
keysym h = h H Left 
keysym l = l L Right
keysym k = k K Up
keysym j = j J Down
keysym u = u U Home
keysym m = m M End
keysym y = y Y BackSpace
keysym n = n N Delete

execute re-mapping, permanent solution

# vim /etc/profile
xmodmap $HOME/.config/xmodmap-hjkl

remap reset, reset xmodmap

setxkbmap -option

terminal title

set-title(){
  ORIG=$PS1
  TITLE="\e]2;$@\a"
  PS1=${ORIG}${TITLE}
}

set-title "my title for terminal"

code/decode

base64

# !!! important !!! will produce line with suffix "\n" 
base64 cAdvisor-start.sh | base64 --decode
echo "just a text string" | base64 | base64 --decode

# !!! important !!! will produce line WITHOUT suffix "\n" 
echo -n "just a text string " | base64 
printf "just a text string " | base64

md5 digest

echo -n foobar | sha256sum

md5sum filename
sha224sum filename
sha384sum filename
sha512sum filename

check pgp signature check control sum

sig_file=`ls ~/Downloads/*.sig`
original_file="${sig_file%.sig}"
gpg --verify $sig_file $original_file

check open pgp signature

# tails-amd64-5.22.img   tails-amd64-5.22.img.sig   tails-signing.key
gpg --import tails-signing.key
gpg --verify tails-amd64-5.22.img.sig tails-amd64-5.22.img

driver install hardware

sudo ubuntu-drivers autoinstall
reboot

hardware serial numbers, hardware id, hardware version, system info

sudo dmidecode --string system-serial-number
sudo dmidecode --string processor-family
sudo dmidecode --string system-manufacturer
# disk serial number
sudo lshw -class disk

equipment system devices

inxi -C
inxi --memory
inxi -CfxCa

images

convert image from jpg to jpg, transform image from one format to another

convert input.png output.jpg
convert input.png -crop $WIDTHx$HEIGHT+$X+$Y output.jpg

qr code online generator

http://goqr.me/api/doc/create-qr-code/
http://api.qrserver.com/v1/create-qr-code/?data=HelloWorld!&size=100x100
https://qr-creator.com/url.php
https://qrgenerator.org/

qr code generator

# generate qrcode
# sudo apt install qrencode
qrencode --size 6 --level H --output="test-text.png" "test text"
echo "output from pipe" | qrencode --size 6 --level H --output="test-text.png"

bar code scanner qr code scanner

# bar code scanner QR code scanner
sudo apt install zbar-tools
zbarimg ~/path-to-screenshot-of-barcode.png

bar code finder

apt install zbar-tool
zbarimg <file>

image file with bar code

barcode - for pdf only

convert text to image

# list of all fonts: `fc-list`
# transparent background: xc:none
convert -size 800x600     xc:white -font "Garuda" -pointsize 20 -fill black -annotate +50+50 "some text\n and more \n lines" $OUTPUT_FILE

insert image into another image, image composition

convert input_image.jpg output_image.png -composite overlay_image.png -gravity center
convert input_image.jpg output_image.png -composite overlay_image.png -geometry 50%x50%+0+0

pdf

convert pdf to image

FILE_SOURCE="certificate_Vitalii.pdf"
pdftoppm -png $FILE_SOURCE  $FILE_SOURCE
# pdftoppm -mono -jpeg $FILE_SOURCE $FILE_SOURCE

# tesseract $FILE_SOURCE-1.png - -l eng

convert -geometry 400x600 -density 100x100 -quality 100 test-pdf.pdf test-pdf.jpg

bar code create into pdf

barcode -o 1112.pdf -e "code39" -b "1112" -u "mm" -g 50x50

pdf file merge, pdf join

# -dAutoRotatePages=/None 
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished.pdf test-pdf2.pdf test-pdf3.pdf test-pdf4.pdf
rm finished.pdf; gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished.pdf -dDEVICEWIDTH=612 -dDEVICEHEIGHT=792 *.pdf
rm finished.pdf; gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished.pdf -dDEVICEWIDTH=612 -dDEVICEHEIGHT=792 -dPAGEWIDTH=612 -dPAGEHEIGHT=792 -dFIXEDMEDIA *.pdf

for each_file in `*.pdf`; do
    gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$each_file-resized" "$each_file"
done

rm finished.pdf; pdftk *.pdf cat output finished.pdf

pdf file decrease size pdf compression

# -dPDFSETTINGS=/screen — Low quality and small size at 72dpi.
# -dPDFSETTINGS=/ebook — Slightly better quality but also a larger file size at 150dpi.
# -dPDFSETTINGS=/prepress — High quality and large size at 300 dpi.
# -dPDFSETTINGS=/default — System chooses the best output, which can create larger PDF files.

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

doc to pdf, convert to pdf

libreoffice --headless --convert-to pdf "/home/path/Dativ.doc" --outdir /tmp/output

pdf to text, extract text from pdf, convert pdf to text

pdftotext file.pdf -

zip

unzip bz2

bzip2 -dc ricochet-1.1.4-src.tar.bz2 | tar xvf -

gzip unzip gzip decompress

gzip -d out.gz
# unknown suffix -- ignored
# add "gz" suffix to file

console and clipboard

alias clipboard="xclip -selection clipboard" 
alias clipboard-ingest="xclip -selection clipboard"
function clipboard-copy-file(){
    xclip -in -selection c $1
}
alias clipboard-print="xclip -out -selection clipboard"

screenshot, copy screen

screenshot(){
	file_name="/home/user/Pictures/screenshots/screenshot_"`date +%Y%m%d_%H%M%S`".png"
	scrot $file_name -s -e "xdg-open $file_name"
}

printer managing ( add/remote/edit )

printer installation
admin page
help page

in case of authorization issue:

/etc/cups/cupsd.conf and changed the AuthType to None and commented the Require user @SYSTEM:

<Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default CUPS-Get-Devices>
AuthType None
# AuthType Default
# Require user @SYSTEM
Order deny,allow
</Limit>

and restart the service

sudo service cups restart

default printer

# show all printer drivers in system
lpinfo -m

# print all printer names
lpstat -l -v
# device for Brother_HL_L8260CDW_series: implicitclass://Brother_HL_L8260CDW_series/

# set default printer
PRINTER_NAME=Brother_HL_L8260CDW_series
sudo lpadmin -d $PRINTER_NAME

printer queue

lpq -P

print to printer

lpr -P $PRINTER_NAME myfile.txt
lpr -P $PRINTER_NAME -o fit-to-page=false -o position=top $out_file

kernel related messages

dmesg --level=err,warn
dmesg --follow
# save all messages /var/log/dmesg
dmesg -S

disk usage

df -ha
# with visualization
ncdu

create startup disk, write iso image, usb stick, bootable drive, restore disk image

default ubuntu disk startup disk creator

for CD iso images

usb-creator-gtk

https://etcher.balena.io/

https://calamares.io/

startup/bootable usb disk

for LIVE images

# list of all hard drives, disk list
sudo lshw -class disk -short
# write image
sudo dd bs=4M if=/home/my-user/Downloads/archlinux-2019.07.01-x86_64.iso of=/dev/sdb status=progress && sync

startup/bootable usb with persistence, create usb live with persistence, usb persistence, stick persistence

for parallel disk solution Parrot is highly recommended ( good bootloader )

sudo add-apt-repository universe
sudo add-apt-repository ppa:mkusb/ppa
sudo apt-get update
sudo apt install --install-recommends mkusb mkusb-nox usb-pack-efi

# https://parrotsec.org/download/
wget https://deb.parrot.sh/parrot/iso/6.0/Parrot-home-6.0_amd64.iso; cd ~/Downloads
mkusb Parrot-home-6.0_amd64.iso
# Install, persistent live, uefi
# steps: p(persistent), p(dus-Persistent)

split usb drive, split disk

# detect disks
sudo lshw -class disk -short
sudo fdisk -l

# format drive
DEST_DRIVE=/dev/sdb
sudo dd if=/dev/zero of=$DEST_DRIVE  bs=512  count=1
# sudo mke2fs -t xfs $DEST_DRIVE

# split drive, split disk, split usb
sudo parted $DEST_DRIVE

print
rm 1
rm 2

mklabel kali
msdos

mkpart primary ext4 0.0 5GB
I

mkpart extended ntfs 5GB -1s

print 
set 1 boot on
set 2 lba on
quit

sudo fdisk -l

time command resource consumption command exec information

\time -v date

command time consumption

time curl google.com

elapsed time between two commands

STARTTIME=$SECONDS
sleep 2
echo $SECONDS-$STARTTIME

STARTTIME=`date +%s.%N`
sleep 2.5
ENDTIME=`date +%s.%N`
TIMEDIFF=`echo "$ENDTIME - $STARTTIME" | bc | awk -F"." '{print $1"."substr($2,1,3)}'`

language translator

sudo apt-get install translate-shell
trans -source de -target ru -brief "german sentance"

gnome

remove emoji

ibus-setup
# go to emojii and remove shortcuts

video

join mp4 fusion mp4

ffmpeg -i video.mp4 -i audio.mp4 output.mp4

join images to mp4, convert images to video

# in the current folder there are JPEG files in proper order
ffmpeg -framerate 0.5 -pattern_type glob -i "*.jpeg" output.mp4

convert webm video to mp3

FILE_INPUT=video.webm
FILE_OUTPUT=audio.mp3
ffmpeg -i $FILE_INPUT -vn -ab 64k -ar 44100 -y $FILE_OUTPUT

convert mp4 to mp3 with slow playing

file_input="Cybercity.mp4"
file_output="Cybercity.mp3"
ffmpeg -i $file_input -vn -acodec libmp3lame -q:a 4 -filter:a "atempo=0.75 "$file_output

sound

join files

sox 1.wav 2.wav 3.wav 4.wav output.wav
ffmpeg -i 1.wav -i 2.wav -i 3.wav output.wav

split mp3 files

mp3splt -s -p nt=10 album.mp3

copy users, import/export users

sudo awk -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd > passwd-export
sudo awk -F: '($3>=LIMIT) && ($3!=65534)' /etc/group > /opt/group-export
sudo awk -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - | egrep -f - /etc/shadow > /opt/shadow-export
sudo cp /etc/gshadow /opt/gshadow-export

calculcate size of files by type

find . -name "*.java" -ls | awk '{byte_size += $7} END{print byte_size}'

calculcate size of files by type, list of files, sort files by size

du -hs * | sort -h

calculator arithmethic operations add sub div multiply evaluation

expr 30 / 5
myvar=$(expr 1 + 1)

python3 -c "print(4*3)"
perl -e "print 4*3"

desc calculator

echo "2 3 + p" | dc

basic calculator

echo "4+5" | bc
bc <<< 4+5

interactive calculator

bc -l -i

interactive arithmethic calculator

calc
qalc

sudo without password, apple keyboard, sudo script without password

echo 'password' | sudo -S bash -c "echo 2 > /sys/module/hid_apple/parameters/fnmode" 2>/dev/null

default type, detect default browser, mime types, default application set default app

xdg-mime query default x-scheme-handler/http

## where accessible types
# echo $XDG_DATA_DIRS # avaialible in applications
# locate google-chrome.desktop
# /usr/share/applications/google-chrome.desktop

## set default browser 
xdg-mime default firefox.desktop x-scheme-handler/http
xdg-mime default firefox.desktop x-scheme-handler/https
xdg-settings set default-web-browser firefox.desktop

## check default association
cat ~/.config/mimeapps.list
cat /usr/share/applications/defaults.list

or change your alternatives

locate x-www-browser
# /etc/alternatives/x-www-browser

open in default browser

x-www-browser http://localhost:9090

alternatives

set default browser

sudo update-alternatives --display x-www-browser
sudo update-alternatives --query x-www-browser
sudo update-alternatives --remove x-www-browser /snap/bin/chromium
sudo update-alternatives --remove x-www-browser /usr/bin/chromium
sudo update-alternatives --install /usr/bin/x-www-browser x-www-browser /usr/bin/chromium-browser 90

java set default

update-alternatives --install /usr/bin/java java $JAVA_HOME/bin/java 10

open file with default editor, default viewer, with more appropriate viewr

# ranger should be installed 
rifle <path to file>

cat replacement bat

# apt install bat - not working sometimes
cargo install bat
batcat textfile
# alias bat=batcat
bat textfile

install haskell

sudo apt-get install haskell-stack
stack upgrade
stack install toodles

get started with hackell

shell examples

byobu

sudo apt install byobu

check architecture

dpkg --add-architecture i386
dpkg --print-architecture
dpkg --print-foreign-architectures

move mouse, control X server

apt-get install xdotool
# move the mouse  x    y
xdotool mousemove 1800 500
# left click
xdotool click 1

pls, check that you are using Xorg and not Wayland (Window system):

# uncomment false
cat /etc/gdm3/custom.conf | grep WaylandEnable

how to check your current display server(window system):

# x11 - xorg
# wayland
echo $XDG_SESSION_TYPE

another possible solution for moving mouse cursor

apt-get install xautomation
xte 'mousemove 200 200'

another possible solution for moving mouse cursor

calendar, week number

gcal --with-week-number

vnc server

# vnc server 
sudo apt install tigervnc-standalone-server
# tigervncserver

## issue on Ubuntu 22.04
# sudo apt install tightvncserver
# tightvncserver

# vncserver -passwordfile ~/.vnc/passwd -rfbport 5900 -display :0
vncserver
# for changing password
vncpasswd
# list of vnc servers 
vncserver -list
# stop vnc server
vncserver -kill :1
# configuration

vim ~/.vnc/xstartup
# xrdb $HOME/.Xresources
# startxfce4 &

vnc server with connecting to existing X session

# https://github.com/sebestyenistvan/runvncserver
sudo apt install tigervnc-scraping-server

## password for VNC server
vncpasswd

## start vnc server 
X0tigervnc -PasswordFile ~/.vnc/passwd
# the same as: `x0vncserver -display :0`
x0vncserver -passwordfile ~/.vnc/passwd -rfbport 5900 -display :0

## list of the servers
x0vncserver -list

## log files 
ls $HOME/.vnc/*.log

x0vncserver -kill :1

apt

apt package description

apt-cache show terminator

apt cache

cd /var/cache/apt/archives

apt force install

sudo apt install --fix-broken -o Dpkg::Options::="--force-overwrite" {package name}

Issues

issue with go package installation

>pkg-config --cflags  -- devmapper
Package devmapper was not found in the pkg-config search path.
Perhaps you should add the directory containing `devmapper.pc'
to the PKG_CONFIG_PATH environment variable
No package 'devmapper' found

sudo apt install libdevmapper-dev
export PKG_CONFIG_PATH=`echo $(pkg-config --variable pc_path pkg-config)${PKG_CONFIG_PATH:+:}${PKG_CONFIG_PATH}`

Files

linux-cheat-sheet.md

Latest commit

History

linux-cheat-sheet.md

File metadata and controls

Linux Debian cheat sheet

commands gnu commands

retrieve human readable information from binary files

place for scripts, permanent script

socket proxy, proxy to remote machine

jumpserver proxy jump host bastion

scp bastion scp proxy scp copy via bastion

scp error

tunnel, port forwarding from local machine to outside

tunnel, port forwarding from outside to localmachine

tunnel for remote machine with proxy, local proxy for remote machine, remote proxy access

ssh suppress banner, ssh no invitation

ssh verbosive, ssh log, debug ssh

ssh variable ssh envvar ssh send variable

ssh variable in command line

sshd config

ssh environment, execute on remote server bash file after login

ssh run command

local proxy cntlm, cntlm proxy

possible solution to detect remote client to your machine

open ports, open connections, listening ports, application by port, application port, process port, pid port

mount drive to path mount

mount remote filesystem via ssh, map folder via ssh, ssh remote folder

mount remote filesystem via ftp

samsung phone android phone folder

mount windows folder, mount windows shared folder

mount issue

mount usb drive temporary mount disk

unmount usb detach usb

mount usb drive permanently mount, map drive

drive uuid hdd uuid

list drives, drive list, attached drives

create filesystem, format drive

gpg signature check, asc signature check, crt signature check

authenticator 2fa

connect to remote machine via ssh without credentials

print public ssh keys, ssh public keys

passphrase skip typing ssh-keygen without passphrase, avoid Enter passphrase for key

login without typing password

login without typing password

copy ssh key to remote machine,

automate copying password

ssh fingerprint checking

manage multiply keys

copy from local machine to remote one, remote copy

copy from remote machine to local

copy directory to remote machine, copy folder to remote machine

copy file with saving all attributes, copy attributes, copy file with attributes

copy only when changed

change owner

rsync singe file copy from remote

sync folders synchronize folders, copy everything between folders, diff folder

create directory on remote machine, create folder remotely, ssh execute command, ssh remote execution

ssh execute command and detach ssh execute detached ssh command SIGHUP Signal Hang UP

ssh xserver, ssh graphical

option1

option 2

here document, sftp batch command with bash

map folder to another path, mount dir to another location

mount cdrom ( for virtual machine )

create ram disc

repeat command with predefined interval, execute command repeatedly, watch multiple command watch pipe

execute command in case of changes watch file

repeat last command

repeat last command with substring "flow" included into whole command line

execute in current dir, inline shell execution

directories into stack

to previous folder

sudo reboot

sort, order

print file with line numbers, output linenumbers

split and join big files split and merge, make parts from big file copy parts

cut big file, split big file, cat after threshold

unique lines (duplications) into file