user/zeropad.sh

   1 #!/bin/bash
   2 # Desc: Zero-pad working dir files with initial digits for sorting
   3 # Usage: zeropad.sh [str fext]
   4 # Example: zeropad.sh;
   5 #          zeropad.sh ".jpg";
   6 # Input: arg1  str  file extension of files to apply changes to
   7 # Version: 0.2.0
   8
   9 declare fext; # file extension
  10
  11 list_files() {
  12     # Desc: Lists working directory file basenames
  13     # Usage: list_files
  14     # Input: fext  var  file extension
  15     # Output: stdout  a line-delimited list of file names
  16     if [[ -z "$fext" ]]; then
  17         find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; ;
  18     else
  19         find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; \
  20             | grep -E -- "${fext}$" ;
  21     fi;
  22 }; # list pwd file basenames
  23 remove_leading_zeroes() {
  24     # Desc: Removes leading zeroes from lines
  25     # Input: stdin
  26     # Output: stdout
  27     # Depends: BK-2020-03 read_stdin()
  28     # Version: 0.0.1
  29     while read -r line; do
  30         printf "%s\n" "$line" | sed -E -e 's/(^0*)([0-9].*)/\2/';
  31     done;
  32 };
  33 get_max_digits() {
  34     # Desc: Returns max leading digits of pwd filenames
  35     # Depends: list_files()
  36     #          BK-2020-03:  remove_leading_zeroes()
  37     #          GNU sed 4.8
  38     #          GNU awk 5.1.0
  39     local output;
  40
  41     # Find the maximum number of leading digits in the filenames of working dir
  42     output="$(list_files | remove_leading_zeroes \
  43         | awk '{ match($0, /^[0-9]+/); if (RLENGTH > max) max=RLENGTH } END { print max }' )";
  44     # declare -p max_digits; # debug
  45     printf "%s" "$output";
  46 }; # return max digits to stdout
  47 main () {
  48     # Read file extension if provided
  49     if [[ -n "$1" ]]; then
  50         fext="$1";
  51     fi;
  52
  53     max_digits="$(get_max_digits)";
  54
  55     # Loop over the files and rename them
  56     while read -r file; do
  57         # Skip files with no leading digits
  58         re='^[0-9]+';
  59         if [[ ! "$file" =~ $re ]]; then continue; fi;
  60
  61         # Extract the leading digits
  62         digits="$(echo "$file" | sed -E 's/([0-9]*).*/\1/')"; # all leading digits
  63         digits_nlz="$(echo "$digits" | remove_leading_zeroes)"; # no leading zeroes
  64         # Zero-pad the digits
  65         padded_digits="$(printf "%0${max_digits}d" "$digits_nlz")";
  66         # Construct the new filename
  67         new_file="${padded_digits}${file#${digits}}";
  68         # Rename the file
  69         if [[ "$file" == "$new_file" ]]; then continue; fi;
  70         mv -n "$file" "$new_file";
  71         #declare -p max_digits file digits digits_nlz padded_digits new_file # debug
  72     done < <(list_files);
  73 }; # main program
  74
  75 main "$@";
  76
  77 # Author: Steven Baltakatei Sandoval
  78 # License: GPLv3+