README.md

Linux Notes

Menu

• shell
• raspberry pi
• apt
• X11

shell

bash

• remove double quotes.
  • all "${opt//\"}"
  • suffix "${opt%\"}"
  • prefix "${opt#\"}"

zsh

• Prompt only displays the basename of the current directory.
  Change %~ to %1~
  Reference

raspberry pi

• headless wifi
  wpa_supplicant.conf

  country=US
  ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
  update_config=1
  
  network={
  	ssid="your_real_wifi_ssid"
  	scan_ssid=1
  	psk="your_real_password"
  	key_mgmt=WPA-PSK
  }
  

• headless ip address setup
  add a line in cmdline.txt
  ip=192.168.0.10

apt

• sudo dpkg -i --force-overwrite /var/cache/apt/archives/apport_2.20.1-0ubuntu2.4_all.deb

X11

Solution for Warning: No xauth data; using fake authentication data for X11 forwarding.

• at local(client) machine.

  touch ~/.Xauthority
  xauth generate $DISPLAY .

Issues

• Local sites running in WSL2 not accessible in browser
  • the windows docker edits the host file. it works well after reseting the host file.

asdf with brew

• echo -e "\n. $(brew --prefix asdf)/libexec/asdf.sh" >> ${ZDOTDIR:-~}/.myshell.sh
• failed to use asdf zsh plugin

Emacs

The emacs daemon can be started automatically in a very simple manner. export ALTERNATE_EDITOR=""

ulimit -n in WSL2:

problem: https://askubuntu.com/a/1327539 walkaround: microsoft/WSL#6226

sudo

• How to make sudo preserve $PATH?