From 59044e2d2ad4b3e4653ad95810eec5a9ff998e29 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Mon, 28 Aug 2023 12:35:45 +0800
Subject: [PATCH 01/10] =?UTF-8?q?refactor/robust(`c`):=20use=20`printf`=20?=
 =?UTF-8?q?=F0=9F=92=AA=20instead=20of=20`echo`;=20use=20`if-else`=20inste?=
 =?UTF-8?q?ad=20of=20`&&-||`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/bin/c b/bin/c
index 7c023d63..9f65eee4 100755
--- a/bin/c
+++ b/bin/c
@@ -35,12 +35,14 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
-
-redEcho() {
-  [ -t 1 ] && echo "${ec}[1;31m$*$eend" || echo "$*"
+printErrorMsg() {
+  # check isatty in bash https://stackoverflow.com/questions/10022323
+  # if stdout is console, print with red color.
+  if [ -t 1 ]; then
+    printf "\033[1;31m%s\033[0m\n\n" "Error: $*"
+  else
+    printf '%s\n\n' "Error: $*"
+  fi
 }
 
 usage() {
@@ -49,7 +51,7 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  (($# > 0)) && printErrorMsg "$*" >$out
 
   cat >$out <<EOF
 Usage: ${PROG} [OPTION]... [command [command_args ...]]
@@ -73,7 +75,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -106,7 +108,7 @@ while [ $# -gt 0 ]; do
     break
     ;;
   -*)
-    usage 2 "${PROG}: unrecognized option '$1'"
+    usage 2 "unrecognized option '$1'"
     ;;
   *)
     # if not option, treat all follow args as command

From 1dcead5c3ff666138cd0cec4565c9478eae63c2a Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Mon, 28 Aug 2023 12:39:53 +0800
Subject: [PATCH 02/10] =?UTF-8?q?refactor/robust(`coat/a2l`):=20use=20`pri?=
 =?UTF-8?q?ntf`=20=F0=9F=92=AA=20instead=20of=20`echo`;=20the=20`echo`=20o?=
 =?UTF-8?q?ption(e.g.=20-e=20-n)=20may=20effect=20correctness=20?=
 =?UTF-8?q?=F0=9F=90=9E=20,=20`printf`=20is=20more=20robust=20=F0=9F=92=AA?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 bin/a2l  | 34 +++++++++++++++-------------------
 bin/coat | 16 ++++++----------
 2 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/bin/a2l b/bin/a2l
index f940fa51..6ab30820 100755
--- a/bin/a2l
+++ b/bin/a2l
@@ -1,6 +1,6 @@
 #!/bin/bash
 # @Function
-# echo each arguments on one line colorfully.
+# print each arguments on one line colorfully.
 #
 # @Usage
 #   $ ./a2l arg1 arg2
@@ -19,26 +19,22 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-
-colorEcho() {
+colorPrint() {
   local color="$1"
   shift
   # check isatty in bash https://stackoverflow.com/questions/10022323
   # if stdout is console, turn on color output.
-  [ -t 1 ] && echo "${ec}[1;${color}m$*${eend}" || echo "$*"
-}
-
-redEcho() {
-  colorEcho 31 "$@"
+  if [ -t 1 ]; then
+    printf "\033[1;${color}m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
 usage() {
   cat <<EOF
 Usage: ${PROG} [OPTION]... ARG...
-echo each arguments on one line colorfully.
+print each arguments on one line colorfully.
 
 Example:
   ${PROG} arg1 arg2
@@ -53,7 +49,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -94,20 +90,20 @@ readonly args
 # biz logic
 ################################################################################
 
-readonly -a ECHO_COLORS=(33 35 36 31 32 37 34)
+readonly -a ROTATE_COLORS=(33 35 36 31 32 37 34)
 COUNT=0
-rotateColorEcho() {
+rotateColorPrint() {
   local message="$*"
 
   # skip color for white space
   if [[ "$message" =~ ^[[:space:]]*$ ]]; then
-    echo "$message"
+    printf '%s\n' "$message"
   else
-    local color="${ECHO_COLORS[COUNT++ % ${#ECHO_COLORS[@]}]}"
-    colorEcho "$color" "$*"
+    local color="${ROTATE_COLORS[COUNT++ % ${#ROTATE_COLORS[@]}]}"
+    colorPrint "$color" "$*"
   fi
 }
 
 for a in ${args[@]:+"${args[@]}"}; do
-  rotateColorEcho "$a"
+  rotateColorPrint "$a"
 done
diff --git a/bin/coat b/bin/coat
index a86c2c0f..496bf7ef 100755
--- a/bin/coat
+++ b/bin/coat
@@ -15,26 +15,22 @@ set -eEuo pipefail
 #   check isatty in bash https://stackoverflow.com/questions/10022323
 [ ! -t 1 ] && exec cat "$@"
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-
-readonly -a ECHO_COLORS=(33 35 36 31 32 37 34)
+readonly -a ROTATE_COLORS=(33 35 36 31 32 37 34)
 COUNT=0
-rotateColorEcho() {
+rotateColorPrint() {
   local message="$*"
 
   # skip color for white space
   if [[ "$message" =~ ^[[:space:]]*$ ]]; then
-    echo "$message"
+    printf '%s\n' "$message"
   else
-    local color="${ECHO_COLORS[COUNT++ % ${#ECHO_COLORS[@]}]}"
-    echo "${ec}[1;${color}m$message$eend"
+    local color="${ROTATE_COLORS[COUNT++ % ${#ROTATE_COLORS[@]}]}"
+    printf "\033[1;${color}m%s\033[0m\n" "$message"
   fi
 }
 
 # Bash read line does not read leading spaces
 # https://stackoverflow.com/questions/29689172
 cat "$@" | while IFS= read -r line; do
-  rotateColorEcho "$line"
+  rotateColorPrint "$line"
 done

From ddb91c7c593e1bb050c894757c7236758dcc5885 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Mon, 28 Aug 2023 12:43:33 +0800
Subject: [PATCH 03/10] =?UTF-8?q?refactor/robust(`echo-args`):=20use=20`pr?=
 =?UTF-8?q?intf`=20=F0=9F=92=AA=20instead=20of=20`echo`;=20align=20the=20i?=
 =?UTF-8?q?ndex=20number?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 bin/echo-args | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/bin/echo-args b/bin/echo-args
index 82b76859..a2dd472a 100755
--- a/bin/echo-args
+++ b/bin/echo-args
@@ -6,20 +6,37 @@
 # @author Jerry Lee (oldratlee at gmail dot com)
 set -eEuo pipefail
 
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
+digitCount() {
+  # argument 1(num) is always a non-negative integer in this script usage,
+  # so NO argument validation logic.
+  local num="$1" count=0
+  while ((num != 0)); do
+    ((++count))
+    ((num = num / 10))
+  done
+  echo "$count"
+}
+
+digit_count=$(digitCount $#)
+readonly arg_count=$# digit_count
+
+readonly red='\033[1;31m'
+readonly blue='\033[1;36m'
+readonly normal='\033[0m'
 
-echoArg() {
-  local index="$1" count="$2" value="$3"
+printArg() {
+  local idx="$1" value="$2"
 
   # if stdout is console, turn on color output.
-  [ -t 1 ] &&
-    echo "${index}/${count}: ${ec}[1;31m[$eend${ec}[1;36;40m$value$eend${ec}[1;31m]$eend" ||
-    echo "${index}/${count}: [${value}]"
+  if [ -t 1 ]; then
+    printf "%${digit_count}s/%s: ${red}[${blue}%s${red}]${normal}\n" "$idx" "$arg_count" "$value"
+  else
+    printf "%${digit_count}s/%s: [%s]\n" "$idx" "$arg_count" "$value"
+  fi
 }
 
-echoArg 0 $# "$0"
+printArg 0 "$0"
 idx=1
 for a; do
-  echoArg $((idx++)) $# "$a"
+  printArg $((idx++)) "$a"
 done

From e9f69f7f0a008ec66139fc1c41e0b56afa1aa48c Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Mon, 28 Aug 2023 13:25:05 +0800
Subject: [PATCH 04/10] =?UTF-8?q?refactor/robust(`find-in-jars`):=20use=20?=
 =?UTF-8?q?`printf`=20=F0=9F=92=AA=20instead=20of=20`echo`;=20use=20`if-el?=
 =?UTF-8?q?se`=20instead=20of=20`&&-||`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/find-in-jars | 63 ++++++++++++++++++++++++++++--------------------
 1 file changed, 37 insertions(+), 26 deletions(-)

diff --git a/bin/find-in-jars b/bin/find-in-jars
index efcd9e24..5f393589 100755
--- a/bin/find-in-jars
+++ b/bin/find-in-jars
@@ -40,10 +40,9 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
+readonly red='\033[1;31m' normal='\033[0m'
+readonly jar_color='\033[1;35m' sep_color='\033[1;32m'
+
 # How to delete line with echo?
 # https://unix.stackexchange.com/questions/26576
 #
@@ -52,11 +51,15 @@ readonly nl=$'\n'        # new line
 # echo -e "\033[1K"
 # Or everything on the line, regardless of cursor position:
 # echo -e "\033[2K"
-readonly clear_line=$'\033[2K\r'
+readonly clear_line='\033[2K\r'
 
-redEcho() {
+redPrint() {
   # -t check: is a terminal device?
-  [ -t 1 ] && echo "${ec}[1;31m$*$eend" || echo "$*"
+  if [ -t 1 ]; then
+    printf "${red}%s${normal}\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
 # Getting console width using a bash script
@@ -72,7 +75,7 @@ printResponsiveMessage() {
 
   local message="$*"
   # http://www.linuxforums.org/forum/red-hat-fedora-linux/142825-how-truncate-string-bash-script.html
-  echo -n "$clear_line${message:0:columns}" >&2
+  printf "${clear_line}%s" "${message:0:columns}" >&2
 }
 
 clearResponsiveMessage() {
@@ -80,12 +83,12 @@ clearResponsiveMessage() {
     return
   fi
 
-  echo -n "$clear_line" >&2
+  printf "%b" "$clear_line" >&2
 }
 
 die() {
   clearResponsiveMessage
-  redEcho "Error: $*" >&2
+  redPrint "Error: $*" >&2
   exit 1
 }
 
@@ -95,7 +98,9 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  # NOTE: $'foo' is the escape sequence syntax of bash
+  local -r nl=$'\n' # new line
+  (($# > 0)) && redPrint "$*$nl" >$out
 
   cat >$out <<EOF
 Usage: ${PROG} [OPTION]... PATTERN
@@ -144,7 +149,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -227,7 +232,7 @@ while (($# > 0)); do
     break
     ;;
   -*)
-    usage 2 "${PROG}: unrecognized option '$1'"
+    usage 2 "Error: unrecognized option '$1'"
     ;;
   *)
     args=(${args[@]:+"${args[@]}"} "$1")
@@ -319,7 +324,7 @@ listZipEntries() {
       # exit code is 1, and print 'Empty zipfile.'
       if [ "$msg" != 'Empty zipfile.' ]; then
         clearResponsiveMessage
-        redEcho "fail to list zip entries of $zip_file, ignored: $msg" >&2
+        redPrint "fail to list zip entries of $zip_file, ignored: $msg" >&2
       fi
       return 0
     }
@@ -327,7 +332,7 @@ listZipEntries() {
 
   "${command_to_list_zip_entries[@]}" "$zip_file" || {
     clearResponsiveMessage
-    redEcho "fail to list zip entries of $zip_file, ignored!" >&2
+    redPrint "fail to list zip entries of $zip_file, ignored!" >&2
     return 0
   }
 }
@@ -344,17 +349,18 @@ searchJarFiles() {
   jar_files="$(find "${dirs[@]}" "${find_iname_options[@]}" -type f)"
   [ -n "$jar_files" ] || die "No ${extensions[*]} file found!"
 
-  total_jar_count="$(echo "$jar_files" | wc -l)"
-  # delete white space
-  # because the output of mac system command `wc -l` contains white space!
+  total_jar_count="$(printf '%s\n' "$jar_files" | wc -l)"
+  # remove white space, because the `wc -l` output on mac contains white space!
   total_jar_count="${total_jar_count//[[:space:]]/}"
 
   echo "$total_jar_count"
-  echo "$jar_files"
+  printf '%s\n' "$jar_files"
 }
 
 __outputResultOfJarFile() {
   local jar_file="$1" file
+  # shellcheck disable=SC2206
+  local grep_opt_args=($regex_mode ${ignore_case_option:-} ${grep_color_option:-} -- "$pattern")
 
   if $only_print_file_name; then
     local matched=false
@@ -366,7 +372,7 @@ __outputResultOfJarFile() {
     # - https://stackoverflow.com/questions/19120263/why-exit-code-141-with-grep-q
     # - https://unix.stackexchange.com/questions/305547/broken-pipe-when-grepping-output-but-only-with-i-flag
     # - http://www.pixelbeat.org/programming/sigpipe_handling.html
-    if grep $regex_mode ${ignore_case_option:-} -c -- "$pattern" &>/dev/null; then
+    if grep -c "${grep_opt_args[@]}" &>/dev/null; then
       matched=true
     fi
 
@@ -375,18 +381,23 @@ __outputResultOfJarFile() {
     fi
 
     clearResponsiveMessage
-    [ -t 1 ] && echo "${ec}[1;35m${jar_file}${eend}" || echo "${jar_file}"
+    if [ -t 1 ]; then
+      printf "${jar_color}%s${normal}\n" "${jar_file}"
+    else
+      printf '%s\n' "${jar_file}"
+    fi
   else
     {
       # Prevent grep from exiting in case of no match
       # https://unix.stackexchange.com/questions/330660
-      # shellcheck disable=SC2086
-      grep $regex_mode ${ignore_case_option:-} ${grep_color_option:-} -- "$pattern" || true
+      grep "${grep_opt_args[@]}" || true
     } | while read -r file; do
       clearResponsiveMessage
-      [ -t 1 ] &&
-        echo "${ec}[1;35m${jar_file}${eend}${ec}[1;32m${separator}${eend}${file}" ||
-        echo "${jar_file}${separator}${file}"
+      if [ -t 1 ]; then
+        printf "${jar_color}%s${sep_color}%s${normal}%s\n" "$jar_file" "$separator" "$file"
+      else
+        printf '%s\n' "${jar_file}${separator}${file}"
+      fi
     done
   fi
 }

From 15047b039e151ced56be35a1fa52e1448300d942 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Mon, 28 Aug 2023 20:09:48 +0800
Subject: [PATCH 05/10] =?UTF-8?q?refactor/robust(`ap/rp`):=20improve=20rob?=
 =?UTF-8?q?ustness=20=F0=9F=92=AA=20;=20check=20failure=20and=20reflect=20?=
 =?UTF-8?q?as=20exit=20code;=20improve=20portability(`portableRelPath/port?=
 =?UTF-8?q?ableReadLink`)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- use `printf` 💪 instead of `echo`; use `if-else` instead of `&&-||`
  - the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/ap | 55 +++++++++++++++++++++++-------------
 bin/rp | 89 ++++++++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 100 insertions(+), 44 deletions(-)

diff --git a/bin/ap b/bin/ap
index 901d8055..ea6c984c 100755
--- a/bin/ap
+++ b/bin/ap
@@ -21,25 +21,24 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
-
-colorEcho() {
+colorPrint() {
   local color="$1"
   shift
   # check isatty in bash https://stackoverflow.com/questions/10022323
   # if stdout is console, turn on color output.
-  [ -t 1 ] && echo "${ec}[1;${color}m$*${eend}" || echo "$*"
+  if [ -t 1 ]; then
+    printf "\033[1;${color}m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
-redEcho() {
-  colorEcho 31 "$@"
+redPrint() {
+  colorPrint 31 "$*"
 }
 
 die() {
-  redEcho "Error: $*" 1>&2
+  redPrint "Error: $*" >&2
   exit 1
 }
 
@@ -54,10 +53,15 @@ portableReadLink() {
     readlink -f "$file"
     ;;
   Darwin*)
+    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
     if command -v greadlink >/dev/null; then
       greadlink -f "$file"
+    elif command -v python3 >/dev/null; then
+      python3 "${py_args[@]}"
+    elif command -v python >/dev/null; then
+      python "${py_args[@]}"
     else
-      python -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file"
+      die "fail to find command(greadlink/python3/python) to get absolute path!"
     fi
     ;;
   *)
@@ -72,10 +76,12 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  # NOTE: $'foo' is the escape sequence syntax of bash
+  local nl=$'\n' # new line
+  (($# > 0)) && redPrint "$*$nl" >$out
 
   cat >$out <<EOF
-Usage: ${PROG} [OPTION]... ARG...
+Usage: ${PROG} [OPTION]... [FILE]...
 convert to Absolute Path.
 
 Example:
@@ -91,7 +97,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -115,7 +121,6 @@ while [ $# -gt 0 ]; do
     ;;
   -*)
     usage 2 "${PROG}: unrecognized option '$1'"
-    break
     ;;
   *)
     # if not option, treat all follow files as args
@@ -128,10 +133,20 @@ done
 [ ${#files[@]} -eq 0 ] && files=(.)
 readonly files
 
+################################################################################
+# biz logic
+################################################################################
+
+has_error=false
+
 for f in "${files[@]}"; do
-  ! [ -e "$f" ] && {
-    echo "$f does not exists!"
-    continue
-  }
-  portableReadLink "$f"
+  if [ -e "$f" ]; then
+    portableReadLink "$f"
+  else
+    redPrint "error: $f does not exists!" >&2
+    has_error=true
+  fi
 done
+
+# set exit status
+! $has_error
diff --git a/bin/rp b/bin/rp
index 01ad6c47..b11c5bd8 100755
--- a/bin/rp
+++ b/bin/rp
@@ -21,21 +21,51 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
-
-colorEcho() {
+colorPrint() {
   local color="$1"
   shift
   # check isatty in bash https://stackoverflow.com/questions/10022323
   # if stdout is console, turn on color output.
-  [ -t 1 ] && echo "${ec}[1;${color}m$*${eend}" || echo "$*"
+  if [ -t 1 ]; then
+    printf "\033[1;${color}m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
+}
+
+redPrint() {
+  colorPrint 31 "$@"
 }
 
-redEcho() {
-  colorEcho 31 "$@"
+die() {
+  redPrint "Error: $*" >&2
+  exit 1
+}
+
+portableRelPath() {
+  local file="$1" relTo="$2" uname
+
+  uname="$(uname)"
+  case "$uname" in
+  Linux* | CYGWIN* | MINGW*)
+    realpath "$f" --relative-to="$relTo"
+    ;;
+  Darwin*)
+    local py_args=(-c 'import os, sys; print(os.path.relpath(sys.argv[1], sys.argv[2]))' "$file" "$relTo")
+    if command -v grealpath >/dev/null; then
+      grealpath "$f" --relative-to="$relTo"
+    elif command -v python3 >/dev/null; then
+      python3 "${py_args[@]}"
+    elif command -v python >/dev/null; then
+      python "${py_args[@]}"
+    else
+      die "fail to find command(grealpath/python3/python) to get relative path!"
+    fi
+    ;;
+  *)
+    die "NOT support uname($uname)!"
+    ;;
+  esac
 }
 
 usage() {
@@ -44,15 +74,18 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  # NOTE: $'foo' is the escape sequence syntax of bash
+  local nl=$'\n' # new line
+  (($# > 0)) && redPrint "$*$nl" >$out
 
   cat >$out <<EOF
-Usage: ${PROG} [OPTION]... ARG...
+Usage: ${PROG} [OPTION]... [FILE]...
 convert to Relative Path.
 
 Example:
-  ${PROG} arg1 arg2
-  ${PROG} */*.py
+  ${PROG} path    # relative to current dir
+  ${PROG} path1 relativeToPath
+  ${PROG} */*.c relativeToPath
 
 Options:
   -h, --help      display this help and exit
@@ -63,7 +96,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -87,7 +120,6 @@ while [ $# -gt 0 ]; do
     ;;
   -*)
     usage 2 "${PROG}: unrecognized option '$1'"
-    break
     ;;
   *)
     # if not option, treat all follow files as args
@@ -97,10 +129,7 @@ while [ $# -gt 0 ]; do
   esac
 done
 
-[ "${#files[@]}" -eq 0 ] && {
-  redEcho "Error: NO argument!" 1>&2
-  exit 1
-}
+[ "${#files[@]}" -eq 0 ] && die "NO argument!"
 
 if [ "${#files[@]}" -eq 1 ]; then
   relativeTo=.
@@ -113,12 +142,24 @@ else
 fi
 
 [ -f "$relativeTo" ] && relativeTo="$(dirname "$relativeTo")"
+[ -e "$relativeTo" ] || die "relativeTo dir($relativeTo) does NOT exists!"
+
 readonly files relativeTo
 
+################################################################################
+# biz logic
+################################################################################
+
+has_error=false
+
 for f in "${files[@]}"; do
-  ! [ -e "$f" ] && {
-    echo "$f does not exists!"
-    continue
-  }
-  realpath "$f" --relative-to="$relativeTo"
+  if [ -e "$f" ]; then
+    portableRelPath "$f" "$relativeTo"
+  else
+    redPrint "error: $f does not exists!" >&2
+    has_error=true
+  fi
 done
+
+# set exit status
+! $has_error

From 7d166fe34e5f5cd3e010ef0961b11ca79d84a017 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Tue, 29 Aug 2023 12:40:58 +0800
Subject: [PATCH 06/10] =?UTF-8?q?refactor/robust(`xpl/xpf`):=20improve=20r?=
 =?UTF-8?q?obustness=20=F0=9F=92=AA=20;=20check=20failure=20and=20reflect?=
 =?UTF-8?q?=20as=20exit=20code;=20improve=20portability(`portableRelPath/p?=
 =?UTF-8?q?ortableReadLink`)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- use `printf` 💪 instead of `echo`; use `if-else` instead of `&&-||`
  - the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/xpf | 26 ++++++++++++++++++++++----
 bin/xpl | 46 ++++++++++++++++++++++++++++++++--------------
 2 files changed, 54 insertions(+), 18 deletions(-)

diff --git a/bin/xpf b/bin/xpf
index 3abad3b2..4e6c9dae 100755
--- a/bin/xpf
+++ b/bin/xpf
@@ -1,7 +1,7 @@
 #!/bin/bash
 # @Function
 # Open file in file explorer, file is selected.
-# same as xpl --selected [file [file ...] ]
+# same as xpl --selected [file]...
 #
 # @Usage
 #   $ ./xpf file
@@ -10,6 +10,10 @@
 # @author Jerry Lee (oldratlee at gmail dot com)
 set -eEuo pipefail
 
+################################################################################
+# util functions
+################################################################################
+
 # How can I get the behavior of GNU's readlink -f on a Mac?
 # https://stackoverflow.com/questions/1055671
 portableReadLink() {
@@ -21,10 +25,16 @@ portableReadLink() {
     readlink -f "$file"
     ;;
   Darwin*)
+    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
     if command -v greadlink >/dev/null; then
       greadlink -f "$file"
+    elif command -v python3 >/dev/null; then
+      python3 "${py_args[@]}"
+    elif command -v python >/dev/null; then
+      python "${py_args[@]}"
     else
-      python -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file"
+      echo "fail to find command(greadlink/python3/python) for readlink!" >&2
+      exit 1
     fi
     ;;
   *)
@@ -34,5 +44,13 @@ portableReadLink() {
   esac
 }
 
-BASE="$(dirname "$(portableReadLink "${BASH_SOURCE[0]}")")"
-source "$BASE/xpl" "$@"
+################################################################################
+# biz logic
+################################################################################
+
+# DO NOT inline THIS_SCRIPT into BASE_DIR, because sub-shell:
+#   BASE_DIR="$(dirname "$(portableReadLink "${BASH_SOURCE[0]}")")"
+THIS_SCRIPT="$(portableReadLink "${BASH_SOURCE[0]}")"
+BASE_DIR="$(dirname "$THIS_SCRIPT")"
+
+source "$BASE_DIR/xpl" "$@"
diff --git a/bin/xpl b/bin/xpl
index b197836e..fbad3a37 100755
--- a/bin/xpl
+++ b/bin/xpl
@@ -30,7 +30,9 @@ PROG="$(basename "$0")"
 readonly PROG
 readonly PROG_VERSION='2.5.0-dev'
 
-readonly nl=$'\n' # new line
+################################################################################
+# util functions
+################################################################################
 
 usage() {
   local -r exit_code="${1:-0}"
@@ -38,7 +40,7 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && echo "$*$nl" >$out
+  (($# > 0)) && printf '%s\n\n' "$*" >$out
 
   cat <<EOF
 Usage: ${PROG} [OPTION] [FILE]...
@@ -56,13 +58,10 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
-# if program name is xpf, set option selected!
-[ "xpf" == "${PROG}" ] && selected=true
-
 ################################################################################
 # parse options
 ################################################################################
@@ -96,10 +95,13 @@ while [ $# -gt 0 ]; do
   esac
 done
 
+# if program name is xpf, set option selected!
+[ "xpf" == "${PROG}" ] && selected=true
+
 readonly args selected
 
 ################################################################################
-# biz options
+# biz logic
 ################################################################################
 
 # open one file
@@ -109,33 +111,49 @@ openOneFile() {
   case "$(uname)" in
   Darwin*)
     [ -f "${file}" ] && slt=true
-    open ${slt:+-R} "$file"
+    if $slt; then
+      open -R "$file"
+    else
+      open "$file"
+    fi
     ;;
   CYGWIN*)
     [ -f "${file}" ] && slt=true
-    explorer ${slt:+/select,} "$(cygpath -w "${file}")"
+    if $slt; then
+      explorer /select, "$(cygpath -w "${file}")"
+    else
+      explorer "$(cygpath -w "${file}")"
+    fi
     ;;
   *)
     if [ -d "${file}" ]; then
       nautilus "$(dirname "${file}")"
     else
-      if [ -z "${slt}" ]; then
-        nautilus "$(dirname "${file}")"
-      else
+      if $slt; then
         nautilus "${file}"
+      else
+        nautilus "$(dirname "${file}")"
       fi
     fi
     ;;
   esac
+
+  local selected_msg
+  $slt && selected_msg='with selection'
+  printf 'open %14s: %s\n' "$selected_msg" "$file"
 }
 
 [ "${#args[@]}" == 0 ] && files=(.) || files=("${args[@]}")
+has_error=false
+
 for file in "${files[@]}"; do
   [ ! -e "$file" ] && {
-    echo "$file not existed!"
+    printf '%s\n' "$file not existed!"
     continue
   }
 
   openOneFile "$file"
-  echo "$file opened${selected:+ with selection}!"
 done
+
+# set exit status
+! $has_error

From a17b7c2d25586100553ee08c2e42fbf8ab29afa6 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Wed, 30 Aug 2023 13:08:59 +0800
Subject: [PATCH 07/10] =?UTF-8?q?refactor/robust(`cp-into-docker-run`):=20?=
 =?UTF-8?q?use=20`printf`=20=F0=9F=92=AA=20instead=20of=20`echo`;=20use=20?=
 =?UTF-8?q?`if-else`=20instead=20of=20`&&-||`;=20improve=20portability(`po?=
 =?UTF-8?q?rtableReadLink`)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/cp-into-docker-run | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/bin/cp-into-docker-run b/bin/cp-into-docker-run
index 66648c0b..ffac978b 100755
--- a/bin/cp-into-docker-run
+++ b/bin/cp-into-docker-run
@@ -17,18 +17,17 @@ readonly PROG_VERSION='2.5.0-dev'
 # util functions
 ################################################################################
 
-# NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
-
-redEcho() {
+redPrint() {
   # -t check: is a terminal device?
-  [ -t 1 ] && echo "${ec}[1;31m$*$eend" || echo "$*"
+  if [ -t 1 ]; then
+    printf "\033[1;31m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
 die() {
-  redEcho "Error: $*" 1>&2
+  redPrint "Error: $*" 1>&2
   exit 1
 }
 
@@ -47,10 +46,15 @@ portableReadLink() {
     readlink -f "$file"
     ;;
   Darwin*)
+    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
     if command -v greadlink >/dev/null; then
       greadlink -f "$file"
+    elif command -v python3 >/dev/null; then
+      python3 "${py_args[@]}"
+    elif command -v python >/dev/null; then
+      python "${py_args[@]}"
     else
-      python -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file"
+      die "fail to find command(greadlink/python3/python) for readlink!"
     fi
     ;;
   *)
@@ -65,7 +69,9 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  # NOTE: $'foo' is the escape sequence syntax of bash
+  local nl=$'\n' # new line
+  (($# > 0)) && redPrint "$*$nl" >$out
 
   cat >$out <<EOF
 Usage: ${PROG} [OPTION]... command [command-args]...
@@ -100,7 +106,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -235,7 +241,7 @@ trap cleanupWhenExit EXIT
 ########################################
 
 logAndRun() {
-  $verbose && echo "[$PROG] $*" 1>&2
+  $verbose && printf '%s\n' "[$PROG] $*" 1>&2
   "$@"
 }
 

From e5f5fac46cf69663bde478095fc70b5bef20f71f Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Wed, 30 Aug 2023 13:21:00 +0800
Subject: [PATCH 08/10] =?UTF-8?q?refactor/robust(`tcp-connection-state-cou?=
 =?UTF-8?q?nter/console-text-color-themes.sh`):=20use=20`printf`=20?=
 =?UTF-8?q?=F0=9F=92=AA=20instead=20of=20`echo`;=20use=20`if-else`=20inste?=
 =?UTF-8?q?ad=20of=20`&&-||`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/tcp-connection-state-counter |  3 +-
 lib/console-text-color-themes.sh | 47 +++++++++++++++++++-------------
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/bin/tcp-connection-state-counter b/bin/tcp-connection-state-counter
index 6629e8fb..cbebc013 100755
--- a/bin/tcp-connection-state-counter
+++ b/bin/tcp-connection-state-counter
@@ -35,7 +35,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -58,6 +58,7 @@ done
 # On MacOS, netstat need to using -p tcp to get only tcp output.
 uname | grep Darwin -q && option_for_mac="-ptcp"
 
+# shellcheck disable=SC2086
 netstat -tna ${option_for_mac:-} | awk 'NR > 2 {
     ++s[$NF]
 }
diff --git a/lib/console-text-color-themes.sh b/lib/console-text-color-themes.sh
index dcff9380..63de93ff 100755
--- a/lib/console-text-color-themes.sh
+++ b/lib/console-text-color-themes.sh
@@ -37,55 +37,64 @@ colorEcho() {
   local combination="$1"
   shift 1
 
-  [ -t 1 ] && echo "${_ctct_ec}[${combination}m$*$_ctct_eend" || echo "$*"
+  if [ -t 1 ]; then
+    echo "${_ctct_ec}[${combination}m$*$_ctct_eend"
+  else
+    echo "$*"
+  fi
 }
 
 colorEchoWithoutNewLine() {
   local combination="$1"
   shift 1
 
-  [ -t 1 ] && echo -n "${_ctct_ec}[${combination}m$*$_ctct_eend" || echo -n "$*"
+  if [ -t 1 ]; then
+    echo -n "${_ctct_ec}[${combination}m$*$_ctct_eend"
+  else
+    echo -n "$*"
+  fi
 }
 
 # if not directly run this script(use as lib), just export 2 helper functions,
 # and do NOT print anything.
-[ "$_ctct_is_direct_run" == "true" ] && {
+[ "$_ctct_is_direct_run" == true ] && {
   for style in 0 1 2 3 4 5 6 7; do
     for fg in 30 31 32 33 34 35 36 37; do
       for bg in 40 41 42 43 44 45 46 47; do
         combination="${style};${fg};${bg}"
         colorEchoWithoutNewLine "$combination" "$combination"
-        echo -n " "
+        printf ' '
       done
       echo
     done
     echo
   done
 
-  echo "Code sample to print color text:"
+  echo 'Code sample to print color text:'
 
   echo -n '    echo -e "\033['
-  colorEchoWithoutNewLine "3;35;40" "1;36;41"
-  echo -n "m"
-  colorEchoWithoutNewLine "0;32;40" "Sample Text"
-  echo "\033[0m\""
+  colorEchoWithoutNewLine '3;35;40' '1;36;41'
+  echo -n m
+  colorEchoWithoutNewLine '0;32;40' 'Sample Text'
+  echo '\033[0m"'
 
   echo -n "    echo \$'\033["
-  colorEchoWithoutNewLine "3;35;40" "1;36;41"
+  colorEchoWithoutNewLine '3;35;40' '1;36;41'
   echo -n "m'\""
-  colorEchoWithoutNewLine "0;32;40" "Sample Text"
+  colorEchoWithoutNewLine '0;32;40' 'Sample Text'
   echo "\"$'\033[0m'"
   echo "      # NOTE: $'foo' is the escape sequence syntax of bash, safer escape"
 
-  echo "Output of above code:"
-  echo "    ${_ctct_ec}[1;36;41mSample Text${_ctct_eend}"
+  echo 'Output of above code:'
+  echo -n '    '
+  colorEcho '1;36;41' 'Sample Text'
   echo
-  echo "If you are going crazy to write text in escapes string like me,"
-  echo "you can use colorEcho and colorEchoWithoutNewLine function in this script."
+  echo 'If you are going crazy to write text in escapes string like me,'
+  echo 'you can use colorEcho and colorEchoWithoutNewLine function in this script.'
   echo
-  echo "Code sample to print color text:"
+  echo 'Code sample to print color text:'
   echo '    colorEcho "1;36;41" "Sample Text"'
-  echo "Output of above code:"
-  echo -n "    "
-  colorEcho "1;36;41" "Sample Text"
+  echo 'Output of above code:'
+  echo -n '    '
+  colorEcho '1;36;41' 'Sample Text'
 }

From b2a6bb6e457d39a93a928c15a55f8f6931d7298c Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Wed, 30 Aug 2023 13:58:55 +0800
Subject: [PATCH 09/10] =?UTF-8?q?refactor/robust(`uq`):=20use=20`printf`?=
 =?UTF-8?q?=20=F0=9F=92=AA=20instead=20of=20`echo`;=20use=20`if-else`=20in?=
 =?UTF-8?q?stead=20of=20`&&-||`;=20use=20`${var#}`=20instead=20of=20`awk`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/uq | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/bin/uq b/bin/uq
index f7b2ebee..bdb59914 100755
--- a/bin/uq
+++ b/bin/uq
@@ -38,20 +38,28 @@ readonly PROG_VERSION='2.5.0-dev'
 ################################################################################
 
 # NOTE: $'foo' is the escape sequence syntax of bash
-readonly ec=$'\033'      # escape char
-readonly eend=$'\033[0m' # escape end
-readonly nl=$'\n'        # new line
-
-redEcho() {
-  [ -t 1 ] && echo "${ec}[1;31m$*$eend" || echo "$*"
+readonly nl=$'\n' # new line
+
+redPrint() {
+  # -t check: is a terminal device?
+  if [ -t 1 ]; then
+    printf "\033[1;31m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
-yellowEcho() {
-  [ -t 1 ] && echo "${ec}[1;33m$*$eend" || echo "$*"
+yellowPrint() {
+  # -t check: is a terminal device?
+  if [ -t 1 ]; then
+    printf "\033[1;33m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
 die() {
-  redEcho "Error: $*" 1>&2
+  redPrint "Error: $*" 1>&2
   exit 1
 }
 
@@ -82,7 +90,7 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && redEcho "$*$nl" >$out
+  (($# > 0)) && redPrint "$*$nl" >$out
 
   cat >$out <<EOF
 Usage: ${PROG} [OPTION]... [INPUT [OUTPUT]]
@@ -121,7 +129,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -156,7 +164,7 @@ while (($# > 0)); do
   --all-repeated=*)
     uq_opt_all_repeated=1
 
-    uq_opt_repeated_method=$(echo "$1" | awk -F= '{print $2}')
+    uq_opt_repeated_method=${1#--all-repeated=}
     [[ $uq_opt_repeated_method == 'none' || $uq_opt_repeated_method == 'prepend' || $uq_opt_repeated_method == 'separate' ]] ||
       usage 1 "$PROG: invalid argument ‘${uq_opt_repeated_method}’ for ‘--all-repeated’${nl}Valid arguments are:$nl  - ‘none’$nl  - ‘prepend’$nl  - ‘separate’"
 
@@ -209,7 +217,7 @@ done
   usage 2 "printing all duplicate lines(-D, --all-repeated) and unique lines(-u, --unique) is meaningless"
 
 [[ $uq_opt_all_repeated == 1 && $uq_opt_repeated_method == none && ($uq_opt_count == 0 && $uq_opt_only_repeated == 0) ]] &&
-  yellowEcho "[$PROG] WARN: -D/--all-repeated=none option without -c/-d option, just cat input simply!" >&2
+  yellowPrint "[$PROG] WARN: -D/--all-repeated=none option without -c/-d option, just cat input simply!" >&2
 
 # NOTE: DO NOT declare var uq_max_input_size as readonly in ONE line!
 uq_max_input_size="$(convertHumanReadableSizeToSize "$uq_max_input_human_readable_size")" ||

From 0942d598eeee3619540834f4191460283dfda507 Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Fri, 1 Sep 2023 00:41:37 +0800
Subject: [PATCH 10/10] =?UTF-8?q?refactor/robust(`show-busy-java-threads`)?=
 =?UTF-8?q?:=20use=20`printf`=20=F0=9F=92=AA=20instead=20of=20`echo`;=20us?=
 =?UTF-8?q?e=20`if-else`=20instead=20of=20`&&-||`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NOTE:

- the `echo` option(e.g. -e -n) may effect correctness, `printf` is more robust 💪
- about `&&-||` see shell check:
  https://www.shellcheck.net/wiki/SC2015
---
 bin/show-busy-java-threads | 91 ++++++++++++++++++++------------------
 1 file changed, 49 insertions(+), 42 deletions(-)

diff --git a/bin/show-busy-java-threads b/bin/show-busy-java-threads
index 4abd1778..2e761a96 100755
--- a/bin/show-busy-java-threads
+++ b/bin/show-busy-java-threads
@@ -53,59 +53,66 @@ readonly ec=$'\033'      # escape char
 readonly eend=$'\033[0m' # escape end
 readonly nl=$'\n'        # new line
 
-colorEcho() {
+colorPrint() {
   local color=$1
   shift
 
   # if stdout is console, turn on color output.
-  [ -t 1 ] && echo "${ec}[1;${color}m$*$eend" || echo "$@"
+  if [ -t 1 ]; then
+    printf "\033[1;${color}m%s\033[0m\n" "$*"
+  else
+    printf '%s\n' "$*"
+  fi
 }
 
-colorPrint() {
+__appendToFile() {
+  [[ -n "$append_file" && -w "$append_file" ]] && printf '%s\n' "$*" >>"$append_file"
+  [[ -n "$store_dir" && -w "$store_dir" ]] && printf '%s\n' "$*" >>"${store_file_prefix}$PROG"
+}
+
+colorOutput() {
   local color=$1
   shift
 
-  colorEcho "$color" "$@"
-  [[ -n "$append_file" && -w "$append_file" ]] && echo "$@" >>"$append_file"
-  [[ -n "$store_dir" && -w "$store_dir" ]] && echo "$@" >>"${store_file_prefix}$PROG"
+  colorPrint "$color" "$*"
+  __appendToFile "$*"
 }
 
 # shellcheck disable=SC2120
-normalPrint() {
-  echo "$@"
-  [[ -n "$append_file" && -w "$append_file" ]] && echo "$@" >>"$append_file"
-  [[ -n "$store_dir" && -w "$store_dir" ]] && echo "$@" >>"${store_file_prefix}$PROG"
+normalOutput() {
+  printf '%s\n' "$*"
+  __appendToFile "$*"
 }
 
-redPrint() {
-  colorPrint 31 "$@"
+redOutput() {
+  colorOutput 31 "$*"
 }
 
-greenPrint() {
-  colorPrint 32 "$@"
+greenOutput() {
+  colorOutput 32 "$*"
 }
 
-yellowPrint() {
-  colorPrint 33 "$@"
+yellowOutput() {
+  colorOutput 33 "$*"
 }
 
-bluePrint() {
-  colorPrint 36 "$@"
+blueOutput() {
+  colorOutput 36 "$*"
 }
 
 die() {
-  redPrint "Error: $*" 1>&2
+  redOutput "Error: $*" 1>&2
   exit 1
 }
 
 logAndRun() {
-  echo "$@"
+  printf '%s\n' "$*"
   echo
   "$@"
 }
 
 logAndCat() {
-  echo "$@"
+  printf '%s\n' "$*"
   echo
   cat
 }
@@ -147,7 +154,7 @@ usage() {
   # shellcheck disable=SC2015
   [ "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout
 
-  (($# > 0)) && colorEcho 31 "$*$nl" >$out
+  (($# > 0)) && colorPrint 31 "$*$nl" >$out
 
   cat >$out <<EOF
 Usage: ${PROG} [OPTION]... [delay [count]]
@@ -202,7 +209,7 @@ EOF
 }
 
 progVersion() {
-  echo "$PROG $PROG_VERSION"
+  printf '%s\n' "$PROG $PROG_VERSION"
   exit
 }
 
@@ -386,9 +393,9 @@ cleanupWhenExit() {
 trap cleanupWhenExit EXIT
 
 headInfo() {
-  colorEcho "0;34;42" ================================================================================
-  echo "$(date "+%Y-%m-%d %H:%M:%S.%N") [$((update_round_num + 1))/$update_count]: $(printCallingCommandLine)"
-  colorEcho "0;34;42" ================================================================================
+  colorPrint "0;34;42" ================================================================================
+  printf '%s\n' "$(date "+%Y-%m-%d %H:%M:%S.%N") [$((update_round_num + 1))/$update_count]: $(printCallingCommandLine)"
+  colorPrint "0;34;42" ================================================================================
   echo
 }
 
@@ -434,13 +441,13 @@ findBusyJavaThreadsByPs() {
   [ -n "$ps_out" ] || __die_when_no_java_process_found
 
   if [ -n "$store_dir" ]; then
-    echo "$ps_out" | logAndCat "${ps_cmd_line[*]} | sort -k3,3nr" >"${store_file_prefix}$((update_round_num + 1))_ps"
+    printf '%s\n' "$ps_out" | logAndCat "${ps_cmd_line[*]} | sort -k3,3nr" >"${store_file_prefix}$((update_round_num + 1))_ps"
   fi
 
   if ((count > 0)); then
-    echo "$ps_out" | head -n "${count}"
+    printf '%s\n' "$ps_out" | head -n "${count}"
   else
-    echo "$ps_out"
+    printf '%s\n' "$ps_out"
   fi
 }
 
@@ -473,13 +480,13 @@ __top_threadId_cpu() {
   local top_out
   top_out=$(HOME="$tmp_store_dir" "${top_cmd_line[@]}")
   if [ -n "$store_dir" ]; then
-    echo "$top_out" | logAndCat "${top_cmd_line[@]}" >"${store_file_prefix}$((update_round_num + 1))_top"
+    printf '%s\n' "$top_out" | logAndCat "${top_cmd_line[@]}" >"${store_file_prefix}$((update_round_num + 1))_top"
   fi
 
   # DO NOT combine var result_threads_top_info declaration and assignment in ONE line!
   local result_threads_top_info
   result_threads_top_info=$(
-    echo "$top_out" | awk '{
+    printf '%s\n' "$top_out" | awk '{
             # from text line to empty line, increase block index
             if (previousLine && !$0) blockIndex++
             # only print 4th text block(blockIndex == 3), aka. process info of second top update
@@ -490,7 +497,7 @@ __top_threadId_cpu() {
   )
   [ -n "$result_threads_top_info" ] || __die_when_no_java_process_found
 
-  echo "$result_threads_top_info" | sort -k2,2nr
+  printf '%s\n' "$result_threads_top_info" | sort -k2,2nr
 }
 
 __complete_pid_user_by_ps() {
@@ -501,7 +508,7 @@ __complete_pid_user_by_ps() {
   local ps_out
   ps_out="$("${ps_cmd_line[@]}")"
   if [ -n "$store_dir" ]; then
-    echo "$ps_out" | logAndCat "${ps_cmd_line[@]}" >"${store_file_prefix}$((update_round_num + 1))_ps"
+    printf '%s\n' "$ps_out" | logAndCat "${ps_cmd_line[@]}" >"${store_file_prefix}$((update_round_num + 1))_ps"
   fi
 
   local idx=0 threadId pcpu output_fields
@@ -509,13 +516,13 @@ __complete_pid_user_by_ps() {
     ((count <= 0 || idx < count)) || break
 
     # output field: pid, threadId, pcpu, user
-    output_fields="$(echo "$ps_out" |
+    output_fields="$(printf '%s\n' "$ps_out" |
       awk -v "threadId=$threadId" -v "pcpu=$pcpu" '$2==threadId {
                 print $1, threadId, pcpu, $3; exit
             }')"
     if [ -n "$output_fields" ]; then
       ((idx++))
-      echo "$output_fields"
+      printf '%s\n' "$output_fields"
     fi
   done
 }
@@ -543,20 +550,20 @@ printStackOfThreads() {
         logAndRun sudo -u "${user}" "${jstack_cmd_line[@]}" >"${jstackFile}"
       else
         # current user is not root user, so can not run with sudo; print error message and rerun suggestion
-        redPrint "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
-        redPrint "User of java process($user) is not current user($USER), need sudo to rerun:"
-        yellowPrint "    sudo $(printCallingCommandLine)"
-        normalPrint
+        redOutput "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
+        redOutput "User of java process($user) is not current user($USER), need sudo to rerun:"
+        yellowOutput "    sudo $(printCallingCommandLine)"
+        normalOutput
         continue
       fi || {
-        redPrint "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
-        normalPrint
+        redOutput "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
+        normalOutput
         rm "${jstackFile}" &>/dev/null
         continue
       }
     }
 
-    bluePrint "[$idx] Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user}):"
+    blueOutput "[$idx] Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user}):"
 
     if [ -n "$mix_native_frames" ]; then
       local sed_script="/--------------- $threadId ---------------/,/^---------------/ {