refactor: unify error message format and refactor related functions ℹ️

- keep `usage` function simple
- use `-s`/`-h` option for optional argument of `die` function
- use bash builtin `type -P` instead of `which` command 🐚
- rename var, use `COLOR_INDEX` instead of `COUNT`

bin/a2l

@@ -72,7 +72,7 @@ readonly args
 ################################################################################
 
 readonly -a ROTATE_COLORS=(33 35 36 31 32 37 34)
-COUNT=0
+COLOR_INDEX=0
 rotateColorPrint() {
   local content=$*
   # - if stdout is a terminal, turn on color output.
@@ -82,7 +82,7 @@ rotateColorPrint() {
   if [[ ! -t 1 || $content =~ ^[[:space:]]*$ ]]; then
     printf '%s\n' "$content"
   else
-    local color=${ROTATE_COLORS[COUNT++ % ${#ROTATE_COLORS[@]}]}
+    local color=${ROTATE_COLORS[COLOR_INDEX++ % ${#ROTATE_COLORS[@]}]}
     printf '\e[1;%sm%s\e[0m\n' "$color" "$content"
   fi
 }

bin/ap

@@ -19,23 +19,43 @@ readonly PROG_VERSION='2.x-dev'
 # util functions
 ################################################################################
 
-redPrint() {
+errorMsgPrint() {
+  local errorMsg="$PROG: $*"
   # if stdout is a terminal, turn on color output.
   #   '-t' check: is a terminal?
   #   check isatty in bash https://stackoverflow.com/questions/10022323
   if [ -t 1 ]; then
-    printf '\e[1;31m%s\e[0m\n' "$*"
+    printf '\e[1;31m%s\e[0m\n' "$errorMsg"
   else
-    printf '%s\n' "$*"
+    printf '%s\n' "$errorMsg"
   fi
-}
+} >&2
 
 die() {
-  redPrint "Error: $*" >&2
-  exit 1
-}
-
-# `realpath` command existed on Linux and macOS, return resolved physical path
+  local prompt_help=false exit_status=2
+  while (($# > 0)); do
+    case "$1" in
+    -h)
+      prompt_help=true
+      shift
+      ;;
+    -s)
+      exit_status=$2
+      shift 2
+      ;;
+    *)
+      break
+      ;;
+    esac
+  done
+
+  (($# > 0)) && errorMsgPrint "$*"
+  $prompt_help && echo "Try '$PROG --help' for more information."
+
+  exit "$exit_status"
+} >&2
+
+# `realpath` command exists on Linux and macOS, return resolved physical path
 #   - realpath command on macOS do NOT support option `-e`;
 #     combined `[ -e $file ]` to check file existence first.
 #   - How can I get the behavior of GNU's readlink -f on a Mac?
@@ -45,14 +65,7 @@ realpath() {
 }
 
 usage() {
-  local -r exit_code=${1:-0}
-  (($# > 0)) && shift
-  local -r out=$(((exit_code != 0) + 1))
-
-  # NOTE: $'foo' is the escape sequence syntax of bash
-  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
-
-  cat >&"$out" <<EOF
+  cat <<EOF
 Usage: $PROG [OPTION]... [FILE]...
 convert to Absolute Path.
 
@@ -65,7 +78,7 @@ Options:
   -V, --version   display version information and exit
 EOF
 
-  exit "$exit_code"
+  exit
 }
 
 progVersion() {
@@ -92,7 +105,7 @@ while (($# > 0)); do
     break
     ;;
   -*)
-    usage 2 "$PROG: unrecognized option '$1'"
+    die -h "unrecognized option '$1'"
     ;;
   *)
     # if not option, treat all follow files as args
@@ -113,8 +126,8 @@ has_error=false
 
 for f in "${files[@]}"; do
   realpath "$f" || {
-    redPrint "error: $f does not exists!" >&2
     has_error=true
+    errorMsgPrint "$f: No such file or directory!"
   }
 done
 

bin/c

@@ -18,25 +18,43 @@ readonly PROG_VERSION='2.x-dev'
 # util functions
 ################################################################################
 
-printErrorMsg() {
+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;31m%s\e[0m\n\n' "Error: $*"
+    printf '\e[1;31m%s\e[0m\n' "$*"
   else
-    printf '%s\n\n' "Error: $*"
+    printf '%s\n' "$*"
   fi
 }
 
-usage() {
-  local -r exit_code=${1:-0}
-  (($# > 0)) && shift
-  local -r out=$(((exit_code != 0) + 1))
-
-  (($# > 0)) && printErrorMsg "$*" >&"$out"
+die() {
+  local prompt_help=false exit_status=2
+  while (($# > 0)); do
+    case "$1" in
+    -h)
+      prompt_help=true
+      shift
+      ;;
+    -s)
+      exit_status=$2
+      shift 2
+      ;;
+    *)
+      break
+      ;;
+    esac
+  done
+
+  (($# > 0)) && redPrint "$PROG: $*"
+  $prompt_help && echo "Try '$PROG --help' for more information."
+
+  exit "$exit_status"
+} >&2
 
-  cat >&"$out" <<EOF
+usage() {
+  cat <<EOF
 Usage: $PROG [OPTION]... [command [command_args ...]]
 Run command and put output to system clipper.
 If no command is specified, read from stdin(pipe).
@@ -53,7 +71,7 @@ Options:
   -V, --version   display version information and exit
 EOF
 
-  exit "$exit_code"
+  exit
 }
 
 progVersion() {
@@ -90,7 +108,7 @@ while (($# > 0)); do
     break
     ;;
   -*)
-    usage 2 "unrecognized option '$1'"
+    die -h "unrecognized option '$1'"
     ;;
   *)
     # if not option, treat all follow arguments as command

bin/coat

@@ -18,12 +18,6 @@ readonly PROG_VERSION='2.x-dev'
 # parse options
 ################################################################################
 
-progVersion() {
-  printf '%s version: %s\n' "$PROG" "$PROG_VERSION"
-  printf 'cat executable: %s\n' "$(command -v cat)"
-  exit
-}
-
 usage() {
   cat <<EOF
 Usage: $PROG [OPTION]... [FILE]...
@@ -34,12 +28,18 @@ Support options:
   --version  output version information and exit
 All other options and arguments are delegated to command cat,
 more info see the help/man of command cat(e.g. cat --help).
-cat executable: $(command -v cat)
+cat executable: $(type -P cat)
 EOF
 
   exit
 }
 
+progVersion() {
+  printf '%s version: %s\n' "$PROG" "$PROG_VERSION"
+  printf 'cat executable: %s\n' "$(type -P cat)"
+  exit
+}
+
 args=("$@")
 # check arguments in reverse, so last option wins.
 for ((idx = $# - 1; idx >= 0; --idx)); do
@@ -58,15 +58,15 @@ unset args idx
 [ -t 1 ] || exec cat "$@"
 
 readonly -a ROTATE_COLORS=(33 35 36 31 32 37 34)
-COUNT=0
+COLOR_INDEX=0
 # CAUTION: print content WITHOUT new line
 rotateColorPrint() {
   local content=$*
   # skip color for white space
   if [[ $content =~ ^[[:space:]]*$ ]]; then
     printf %s "$content"
   else
-    local color=${ROTATE_COLORS[COUNT++ % ${#ROTATE_COLORS[@]}]}
+    local color=${ROTATE_COLORS[COLOR_INDEX++ % ${#ROTATE_COLORS[@]}]}
     printf '\e[1;%sm%s\e[0m' "$color" "$content"
   fi
 }

bin/cp-into-docker-run

@@ -28,15 +28,34 @@ redPrint() {
 }
 
 die() {
-  redPrint "Error: $*" >&2
-  exit 1
-}
+  local prompt_help=false exit_staus=2
+  while (($# > 0)); do
+    case "$1" in
+    -h)
+      prompt_help=true
+      shift
+      ;;
+    -s)
+      exit_staus=$2
+      shift 2
+      ;;
+    *)
+      break
+      ;;
+    esac
+  done
+
+  (($# > 0)) && redPrint "$PROG: $*"
+  $prompt_help && echo "Try '$PROG --help' for more information."
+
+  exit "$exit_staus"
+} >&2
 
 isAbsolutePath() {
   [[ "$1" =~ ^/ ]]
 }
 
-# `realpath` command existed on Linux and macOS, return resolved physical path
+# `realpath` command exists on Linux and macOS, return resolved physical path
 #   - realpath command on macOS do NOT support option `-e`;
 #     combined `[ -e $file ]` to check file existence first.
 #   - How can I get the behavior of GNU's readlink -f on a Mac?
@@ -46,14 +65,7 @@ realpath() {
 }
 
 usage() {
-  local -r exit_code=${1:-0}
-  (($# > 0)) && shift
-  local -r out=$(((exit_code != 0) + 1))
-
-  # NOTE: $'foo' is the escape sequence syntax of bash
-  (($# > 0)) && redPrint "$*"$'\n' >&"$out"
-
-  cat >&"$out" <<EOF
+  cat <<EOF
 Usage: $PROG [OPTION]... command [command-args]...
 
 Copy the command into docker container
@@ -82,7 +94,7 @@ miscellaneous:
   -V, --version      display version information and exit
 EOF
 
-  exit "$exit_code"
+  exit
 }
 
 progVersion() {
@@ -140,7 +152,7 @@ while (($# > 0)); do
     break
     ;;
   -*)
-    usage 2 "$PROG: unrecognized option '$1'"
+    die -h "unrecognized option '$1'"
     ;;
   *)
     # if not option, treat all follow arguments as command
@@ -153,7 +165,7 @@ done
 readonly container_name docker_user docker_workdir docker_tmpdir docker_command_cp_path verbose args
 
 [ -n "$container_name" ] ||
-  usage 1 "No destination docker container name, specified by option -c/--container!"
+  die -h "requires destination docker container name, specified by option -c/--container!"
 
 if [ -n "$docker_workdir" ]; then
   isAbsolutePath "$docker_workdir" ||
@@ -171,7 +183,7 @@ fi
 # check docker command existence
 ########################################
 
-command -v docker &>/dev/null || die 'docker command not found!'
+type -P docker &>/dev/null || die 'docker command not found!'
 
 ########################################
 # prepare vars for docker operation