#!/bin/bash
# Desc: Zero-pad working dir files with initial digits for sorting
-# Usage: zeropad.sh
-# Version: 0.0.1
+# Usage: zeropad.sh [str fext]
+# Example: zeropad.sh;
+# zeropad.sh ".jpg";
+# Input: arg1 str file extension of files to apply changes to
+# Version: 0.2.0
-# Find the maximum number of leading digits in the filenames of working dir
-max_digits=$(ls -1 * | sed 's/[^0-9].*//' | awk '{ if(length > L) L=length } END { print L }');
-declare -p max_digits;
+declare fext; # file extension
-# Loop over the files and rename them
-for file in *; do
- # Extract the leading digits
- digits=$(echo "$file" | sed 's/\([0-9]*\).*/\1/');
- # Zero-pad the digits
- padded_digits=$(printf "%0${max_digits}d" "$digits");
- # Construct the new filename
- new_file="${padded_digits}${file#${digits}}";
- # Rename the file
- mv -n "$file" "$new_file"
- # declare -p file new_file; # debug
-done;
+list_files() {
+ # Desc: Lists working directory file basenames
+ # Usage: list_files
+ # Input: fext var file extension
+ # Output: stdout a line-delimited list of file names
+ if [[ -z "$fext" ]]; then
+ find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; ;
+ else
+ find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; \
+ | grep -E -- "${fext}$" ;
+ fi;
+}; # list pwd file basenames
+remove_leading_zeroes() {
+ # Desc: Removes leading zeroes from lines
+ # Input: stdin
+ # Output: stdout
+ # Depends: BK-2020-03 read_stdin()
+ # Version: 0.0.1
+ while read -r line; do
+ printf "%s\n" "$line" | sed -E -e 's/(^0*)([0-9].*)/\2/';
+ done;
+};
+get_max_digits() {
+ # Desc: Returns max leading digits of pwd filenames
+ # Depends: list_files()
+ # BK-2020-03: remove_leading_zeroes()
+ # GNU sed 4.8
+ # GNU awk 5.1.0
+ local output;
+
+ # Find the maximum number of leading digits in the filenames of working dir
+ output="$(list_files | remove_leading_zeroes \
+ | awk '{ match($0, /^[0-9]+/); if (RLENGTH > max) max=RLENGTH } END { print max }' )";
+ # declare -p max_digits; # debug
+ printf "%s" "$output";
+}; # return max digits to stdout
+main () {
+ # Read file extension if provided
+ if [[ -n "$1" ]]; then
+ fext="$1";
+ fi;
+ max_digits="$(get_max_digits)";
+ # Loop over the files and rename them
+ while read -r file; do
+ # Skip files with no leading digits
+ re='^[0-9]+';
+ if [[ ! "$file" =~ $re ]]; then continue; fi;
+
+ # Extract the leading digits
+ digits="$(echo "$file" | sed -E 's/([0-9]*).*/\1/')"; # all leading digits
+ digits_nlz="$(echo "$digits" | remove_leading_zeroes)"; # no leading zeroes
+ # Zero-pad the digits
+ padded_digits="$(printf "%0${max_digits}d" "$digits_nlz")";
+ # Construct the new filename
+ new_file="${padded_digits}${file#${digits}}";
+ # Rename the file
+ if [[ "$file" == "$new_file" ]]; then continue; fi;
+ mv -n "$file" "$new_file";
+ #declare -p max_digits file digits digits_nlz padded_digits new_file # debug
+ done < <(list_files);
+}; # main program
+
+main "$@";
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+