chore: perltidy: rewrite perl-tidy.sh to support single-file tidy

bin/dev/perl-tidy.sh

@@ -1,24 +1,51 @@
 #! /usr/bin/env bash
 # vim: set filetype=sh ts=4 sw=4 sts=4 et:
+set -ueo pipefail
 
 basedir=$(readlink -f "$(dirname "$0")"/../..)
 # shellcheck source=lib/shell/functions.inc
 . "$basedir"/lib/shell/functions.inc
 
-cd "$basedir" || exit 1
+cd "$basedir" || exit 254
 
-if [ "$1" = "test" ]; then
+# $1:
+# - tidy, actually tidy the files in place
+# - test, tell whether the files are tidy without modifying them in place
+
+# $2:
+# - (empty), tidy all files
+# - anything_else, tidy this file
+
+if [ "${1:-}" = "test" ]; then
     params=""
     action_doing "Checking perl tidiness"
-else
+elif [ "${1:-}" = "tidy" ]; then
     params="--backup-and-modify-in-place --backup-file-extension=/tidybak"
     action_doing "Tidying perl files"
+else
+    echo "Usage: $0 <test|tidy> [one_file_name]" >&2
+    exit 1
 fi
 
-# shellcheck disable=SC2086
-find . -type f ! -name "*.tdy" ! -name "*.ERR" ! -name "$(basename $0)" -print0 | \
-    xargs -r0 grep -l 'set filetype=perl' -- | \
-    xargs -r perltidy --paren-tightness=2 --square-bracket-tightness=2 --brace-tightness=2 --maximum-line-length=180 $params
+params="$params \
+    --paren-tightness=2 \
+    --square-bracket-tightness=2 \
+    --brace-tightness=2 \
+    --maximum-line-length=180 \
+"
+
+if [ -z "${2:-}" ]; then
+    # run on all perl files
+    # shellcheck disable=SC2086
+    find . -type f ! -name "*.tdy" ! -name "*.ERR" ! -name "$(basename "$0")" -print0 | \
+        xargs -r0 grep -l 'set filetype=perl' -- | \
+        xargs -r perltidy $params
+else
+    # run on only one file
+    action_detail "${BLUE}$2${NOC}"
+    # shellcheck disable=SC2086
+    perltidy $params "$2"
+fi
 
 bad=""
 nbbad=0