refactor: small code cleanup

- merge `colorPrint` function if only one caller
- remove `local nl=$'\n'` declaration if only one usage
- remove unnecessary `{}` when use var
- use upper-case var name for global readonly vars
- use `=` instead of `==` in `Conditional Expressions`
- improve/fix/add code comments
- remove section comments for simple section

README.md

@@ -11,7 +11,7 @@
 <a href="https://github.com/oldratlee/useful-scripts"><img src="https://img.shields.io/github/repo-size/oldratlee/useful-scripts" alt="GitHub repo size"></a>
 </p>
 
-🐌 useful scripts for making developer's everyday life easier and happier, involved java, shell etc.  
+🐌 useful scripts for making developer's everyday life easier and happier, involved java, shell etc.
 
 👉 平时有用的手动操作做成脚本，以便捷地使用，让开发的日常生活更轻松些。 💕
 
@@ -143,7 +143,7 @@ PS：
 
 - 目前仍然是主流的`Shell`，并且在不同环境基本上都缺省部署了。
 - 在[`Google`的`Shell`风格指南](https://zh-google-styleguide.readthedocs.io/en/latest/google-shell-styleguide/background/)中，明确说到了：`Bash`是**唯一**被允许执行的`shell`脚本语言。
-- 统一用`Bash`，可以避免差异带来的风险与没有收益的复杂性。
+- 统一用`Bash`，可以避免不同`Shell`之间差异所带来的风险与没有收益的复杂性。
     - 有大量的`Shell`实现，`sh`、`bash`、`zsh`、`fish`、`csh`、`tcsh`、`ksh`、`ash`、`dash`……
     - 不同的`Shell`有各种差异，深坑勿入。
 - 个人系统学习过的是`Bash`，比较理解熟悉。
@@ -154,14 +154,14 @@ PS: 虽然交互`Shell`个人已经使用`Zsh` + [`oh-my-zsh`](https://ohmyz.sh/
 
 > 更多资料参见 [子文档](docs/developer-guide.md)。
 
-- 开发规范与工具
-    - [**_`Google Shell Style Guide`_**](https://google.github.io/styleguide/shell.xml) | [中文版](https://zh-google-styleguide.readthedocs.io/en/latest/google-shell-styleguide/background/)
+- 🛠️ 开发规范与工具
+    - [`Google Shell Style Guide`](https://google.github.io/styleguide/shell.xml) | [中文版](https://zh-google-styleguide.readthedocs.io/en/latest/google-shell-styleguide/background/)
     - [`koalaman/shellcheck`](https://github.com/koalaman/shellcheck): `ShellCheck`, a static analysis tool for shell scripts
     - [`mvdan/sh(shfmt)`](https://github.com/mvdan/sh): `shfmt` formats shell programs
 - 👷 **`Bash/Shell`最佳实践与安全编程**文章
     - [Use the Unofficial Bash Strict Mode (Unless You Looove Debugging)](http://redsymbol.net/articles/unofficial-bash-strict-mode/)
     - Bash Pitfalls: 编程易犯的错误 - 团子的小窝：[Part 1](http://kodango.com/bash-pitfalls-part-1) | [Part 2](http://kodango.com/bash-pitfalls-part-2) | [Part 3](http://kodango.com/bash-pitfalls-part-3) | [Part 4](http://kodango.com/bash-pitfalls-part-4) | [英文原文：Bash Pitfalls](http://mywiki.wooledge.org/BashPitfalls)
-    - [不要自己去指定sh的方式去执行脚本](https://github.com/oldratlee/useful-scripts/issues/57#issuecomment-326485965)
+    - [不要自己去指定`sh`的方式去执行脚本](https://github.com/oldratlee/useful-scripts/issues/57#issuecomment-326485965)
 - 🎶 **Tips**
     - [让你提升命令行效率的 Bash 快捷键 【完整版】](https://linuxtoy.org/archives/bash-shortcuts.html)  
       补充：`ctrl + x, ctrl + e` 就地打开文本编辑器来编辑当前命令行，对于复杂命令行特别有用

bin/a2l

@@ -14,7 +14,7 @@ readonly PROG=${0##*/}
 readonly PROG_VERSION='2.x-dev'
 
 ################################################################################
-# util functions
+# parse options
 ################################################################################
 
 usage() {
@@ -39,10 +39,6 @@ progVersion() {
   exit
 }
 
-################################################################################
-# parse options
-################################################################################
-
 args=()
 while (($# > 0)); do
   case "$1" in
@@ -63,13 +59,12 @@ while (($# > 0)); do
     break
     ;;
   *)
-    # if not option, treat all follow arguments as args
+    # if not option, treat it and all follow arguments as args
     args=(${args[@]:+"${args[@]}"} "$@")
     break
     ;;
   esac
 done
-
 readonly args
 
 ################################################################################

bin/ap

@@ -19,23 +19,17 @@ readonly PROG_VERSION='2.x-dev'
 # util functions
 ################################################################################
 
-colorPrint() {
-  local color=$1
-  shift
+redPrint() {
   # if stdout is a terminal, turn on color output.
   #   '-t' check: is a terminal?
   #   check isatty in bash https://stackoverflow.com/questions/10022323
   if [ -t 1 ]; then
-    printf '\e[1;%sm%s\e[0m\n' "$color" "$*"
+    printf '\e[1;31m%s\e[0m\n' "$*"
   else
     printf '%s\n' "$*"
   fi
 }
 
-redPrint() {
-  colorPrint 31 "$*"
-}
-
 die() {
   redPrint "Error: $*" >&2
   exit 1
@@ -75,8 +69,7 @@ usage() {
   local -r out=$(((exit_code != 0) + 1))
 
   # NOTE: $'foo' is the escape sequence syntax of bash
-  local nl=$'\n' # new line
-  (($# > 0)) && redPrint "$*$nl" >&"$out"
+  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
 
   cat >&"$out" <<EOF
 Usage: $PROG [OPTION]... [FILE]...

bin/coat

@@ -72,6 +72,7 @@ rotateColorPrint() {
 }
 
 rotateColorPrintln() {
+  # NOTE: $'foo' is the escape sequence syntax of bash
   rotateColorPrint "$*"$'\n'
 }
 

bin/cp-into-docker-run

@@ -70,8 +70,7 @@ usage() {
   local -r out=$(((exit_code != 0) + 1))
 
   # NOTE: $'foo' is the escape sequence syntax of bash
-  local nl=$'\n' # new line
-  (($# > 0)) && redPrint "$*$nl" >&"$out"
+  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
 
   cat >&"$out" <<EOF
 Usage: $PROG [OPTION]... command [command-args]...

bin/find-in-jars

@@ -79,8 +79,7 @@ usage() {
   local -r out=$(((exit_code != 0) + 1))
 
   # NOTE: $'foo' is the escape sequence syntax of bash
-  local -r nl=$'\n' # new line
-  (($# > 0)) && redPrint "$*$nl" >&"$out"
+  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
 
   cat >&"$out" <<EOF
 Usage: $PROG [OPTION]... PATTERN

bin/rp

@@ -19,23 +19,17 @@ readonly PROG_VERSION='2.x-dev'
 # util functions
 ################################################################################
 
-colorPrint() {
-  local color=$1
-  shift
+redPrint() {
   # if stdout is a terminal, turn on color output.
   #   '-t' check: is a terminal?
   #   check isatty in bash https://stackoverflow.com/questions/10022323
   if [ -t 1 ]; then
-    printf '\e[1;%sm%s\e[0m\n' "$color" "$*"
+    printf '\e[1;31m%s\e[0m\n' "$*"
   else
     printf '%s\n' "$*"
   fi
 }
 
-redPrint() {
-  colorPrint 31 "$@"
-}
-
 die() {
   redPrint "Error: $*" >&2
   exit 1
@@ -73,17 +67,16 @@ usage() {
   local -r out=$(((exit_code != 0) + 1))
 
   # NOTE: $'foo' is the escape sequence syntax of bash
-  local nl=$'\n' # new line
-  (($# > 0)) && redPrint "$*$nl" >&"$out"
+  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
 
   cat >&"$out" <<EOF
-Usage: ${PROG} [OPTION]... [FILE]...
+Usage: $PROG [OPTION]... [FILE]...
 convert to Relative Path.
 
 Example:
-  ${PROG} path    # relative to current dir
-  ${PROG} path1 relativeToPath
-  ${PROG} */*.c relativeToPath
+  $PROG path    # relative to current dir
+  $PROG path1 relativeToPath
+  $PROG */*.c relativeToPath
 
 Options:
   -h, --help      display this help and exit

bin/show-busy-java-threads

@@ -139,14 +139,14 @@ usage() {
   (($# > 0)) && colorPrint 31 "$*$NL" >&"$out"
 
   cat >&"$out" <<EOF
-Usage: ${PROG} [OPTION]... [delay [count]]
+Usage: $PROG [OPTION]... [delay [count]]
 Find out the highest cpu consumed threads of java processes,
 and print the stack of these threads.
 
 Example:
-  ${PROG}       # show busy java threads info
-  ${PROG} 1     # update every 1 second, (stop by eg: CTRL+C)
-  ${PROG} 3 10  # update every 3 seconds, update 10 times
+  $PROG       # show busy java threads info
+  $PROG 1     # update every 1 second, (stop by eg: CTRL+C)
+  $PROG 3 10  # update every 3 seconds, update 10 times
 
 Output control:
   -p, --pid <java pid(s)>   find out the highest cpu consumed threads from
@@ -215,7 +215,7 @@ ARGS=$(
   usage 1
 }
 readonly ARGS
-eval set -- "${ARGS}"
+eval set -- "$ARGS"
 
 count=5
 cpu_sample_interval=0.5
@@ -525,20 +525,20 @@ printStackOfThreads() {
     [ -f "$jstackFile" ] || {
       # shellcheck disable=SC2206
       local -a jstack_cmd_line=("$jstack_path" $force $mix_native_frames $lock_info $pid)
-      if [ "$user" == "$USER" ]; then
+      if [ "$user" = "$USER" ]; then
         # run without sudo, when java process user is current user
         logAndRun "${jstack_cmd_line[@]}" >"$jstackFile"
-      elif [ $UID == 0 ]; then
+      elif ((UID == 0)); then
         # if java process user is not current user, must run jstack with sudo
         logAndRun sudo -u "$user" "${jstack_cmd_line[@]}" >"$jstackFile"
       else
         # current user is not root user, so can not run with sudo; print error message and rerun suggestion
-        redOutput "[$idx] Fail to jstack busy(${pcpu}%) thread($threadId/$threadId0x) stack of java process($pid) under user($user)."
+        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 $(printCallingCommandLine)"
         continue
       fi || {
-        redOutput "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
+        redOutput "[$idx] Fail to jstack busy($pcpu%) thread($threadId/$threadId0x) stack of java process($pid) under user($user)."
         rm "$jstackFile" &>/dev/null
         continue
       }
@@ -582,7 +582,7 @@ main() {
       tee ${append_file:+-a "$append_file"} ${store_dir:+-a "$store_file_prefix$PROG"} >/dev/null
     ((update_count != 1)) && headInfo
 
-    if [ "$cpu_sample_interval" == 0 ]; then
+    if [ "$cpu_sample_interval" = 0 ]; then
       findBusyJavaThreadsByPs
     else
       findBusyJavaThreadsByTop

bin/show-duplicate-java-classes

@@ -24,8 +24,8 @@ from glob import glob
 from io import BytesIO
 from optparse import OptionParser
 from os import walk
-from os.path import relpath, isdir, exists
-from zipfile import ZipFile, BadZipfile
+from os.path import exists, isdir, relpath
+from zipfile import BadZipfile, ZipFile
 
 ################################################################################
 # utils functions

bin/taoc

@@ -72,6 +72,7 @@ rotateColorPrint() {
 }
 
 rotateColorPrintln() {
+  # NOTE: $'foo' is the escape sequence syntax of bash
   rotateColorPrint "$*"$'\n'
 }
 

bin/tcp-connection-state-counter

@@ -14,16 +14,16 @@ readonly PROG=${0##*/}
 readonly PROG_VERSION='2.x-dev'
 
 ################################################################################
-# util functions
+# parse options
 ################################################################################
 
 usage() {
   cat <<EOF
-Usage: ${PROG} [OPTION]...
+Usage: $PROG [OPTION]...
 show count of tcp connection stat.
 
 Example:
-    ${PROG}
+    $PROG
 
 Options:
     -h, --help      display this help and exit
@@ -37,24 +37,20 @@ progVersion() {
   exit
 }
 
-################################################################################
-# parse options
-################################################################################
-
-for a; do
-  [[ "-h" == "$a" || "--help" == "$a" ]] && usage
-done
-
-for a; do
-  [[ "-V" == "$a" || "--version" == "$a" ]] && progVersion
+args=("$@")
+# check arguments in reverse, so last option wins.
+for ((idx = $# - 1; idx >= 0; --idx)); do
+  [[ "${args[idx]}" = -h || "${args[idx]}" = --help ]] && usage
+  [[ "${args[idx]}" = -V || "${args[idx]}" = --version ]] && progVersion
 done
+unset args idx
 
 ################################################################################
 # biz logic
 ################################################################################
 
 # On MacOS, netstat need to using -p tcp to get only tcp output.
-uname | grep Darwin -q && option_for_mac="-ptcp"
+uname | grep Darwin -q && option_for_mac=-ptcp
 
 # shellcheck disable=SC2086
 netstat -tna ${option_for_mac:-} | awk 'NR > 2 {

bin/uq

@@ -20,7 +20,7 @@ readonly PROG_VERSION='2.x-dev'
 ################################################################################
 
 # NOTE: $'foo' is the escape sequence syntax of bash
-readonly nl=$'\n' # new line
+readonly NL=$'\n' # new line
 
 redPrint() {
   # if stdout is a terminal, turn on color output.
@@ -72,10 +72,10 @@ usage() {
   (($# > 0)) && shift
   local -r out=$(((exit_code != 0) + 1))
 
-  (($# > 0)) && redPrint "$*$nl" >&"$out"
+  (($# > 0)) && redPrint "$*$NL" >&"$out"
 
   cat >&"$out" <<EOF
-Usage: ${PROG} [OPTION]... [INPUT [OUTPUT]]
+Usage: $PROG [OPTION]... [INPUT [OUTPUT]]
 Filter lines from INPUT (or standard input), writing to OUTPUT (or standard output).
 Same as \`uniq\` command in core utils,
 but detect repeated lines that are not adjacent, no sorting required.
@@ -147,8 +147,8 @@ while (($# > 0)); do
     uq_opt_all_repeated=1
 
     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’"
+    [[ $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’"
 
     shift
     ;;
@@ -193,12 +193,12 @@ while (($# > 0)); do
   esac
 done
 
-[[ $uq_opt_only_repeated == 1 && $uq_opt_only_unique == 1 ]] &&
+[[ $uq_opt_only_repeated = 1 && $uq_opt_only_unique = 1 ]] &&
   usage 2 "printing duplicated lines(-d, --repeated) and unique lines(-u, --unique) is meaningless"
-[[ $uq_opt_all_repeated == 1 && $uq_opt_only_unique == 1 ]] &&
+[[ $uq_opt_all_repeated = 1 && $uq_opt_only_unique = 1 ]] &&
   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) ]] &&
+[[ $uq_opt_all_repeated = 1 && $uq_opt_repeated_method = none && ($uq_opt_count = 0 && $uq_opt_only_repeated = 0) ]] &&
   yellowPrint "[$PROG] WARN: -D/--all-repeated=none option without -c/-d option, just cat input simply!" >&2
 
 # DO NOT declare and assign var uq_max_input_size(as readonly) in ONE line!
@@ -217,7 +217,7 @@ elif ((argc == 1)); then
 else
   input_files=("${argv[@]:0:argc-1}")
   output_file=${argv[argc - 1]}
-  if [ "$output_file" == - ]; then
+  if [ "$output_file" = - ]; then
     output_file=/dev/stdout
   fi
 fi
@@ -226,7 +226,7 @@ readonly output_file
 # Check input file
 for f in ${input_files[@]:+"${input_files[@]}"}; do
   # - is stdin, ok
-  [ "$f" == - ] && continue
+  [ "$f" = - ] && continue
 
   [ -e "$f" ] || die "input file $f does not exist!"
   [ ! -d "$f" ] || die "input file $f exists, but is a directory!"