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: 0.1.1
   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 main () {
  24     # Read file extension if provided
  25     if [[ -n "$1" ]]; then
  26         fext="$1";
  27     fi;
  28
  29     # Find the maximum number of leading digits in the filenames of working dir
  30     max_digits="$(list_files | sed -e 's/[^0-9].*//' | awk '{ if(length > L) L=length } END { print L }')";
  31     # declare -p max_digits; # debug
  32
  33     # Loop over the files and rename them
  34     while read -r file; do
  35         re='^[0-9]+';
  36         if [[ ! "$file" =~ $re ]]; then continue; fi;
  37
  38         # Extract the leading digits
  39         digits="$(echo "$file" | sed 's/\([0-9]*\).*/\1/')";
  40         # Zero-pad the digits
  41         padded_digits="$(printf "%0${max_digits}d" "$digits")";
  42         # Construct the new filename
  43         new_file="${padded_digits}${file#${digits}}";
  44         # Rename the file
  45         if [[ "$file" == "$new_file" ]]; then continue; fi;
  46         mv -n "$file" "$new_file"
  47         # declare -p file new_file; # debug
  48     done < <(list_files);
  49 }; # main program
  50
  51 main "$@";
  52
  53 # Author: Steven Baltakatei Sandoval
  54 # License: GPLv3+