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 # Version: 0.1.0
   7
   8 declare fext; # file extension
   9
  10 list_files() {
  11     # Desc: Lists working directory file basenames
  12     # Usage: list_files
  13     # Input: fext  var  file extension
  14     # Output: stdout  a line-delimited list of file names
  15     if [[ -z "$fext" ]]; then
  16         find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; ;
  17     else
  18         find . -mindepth 1 -maxdepth 1 -type f -exec basename '{}' \; \
  19             | grep -E -- "${fext}$" ;
  20     fi;
  21 }; # list pwd file basenames
  22 main () {
  23     # Read file extension if provided
  24     if [[ -n "$1" ]]; then
  25         fext="$1";
  26     fi;
  27
  28     # Find the maximum number of leading digits in the filenames of working dir
  29     max_digits="$(list_files | sed -e 's/[^0-9].*//' | awk '{ if(length > L) L=length } END { print L }')";
  30     # declare -p max_digits; # debug
  31
  32     # Loop over the files and rename them
  33     while read -r file; do
  34         re='^[0-9]+';
  35         if [[ ! "$file" =~ $re ]]; then continue; fi;
  36
  37         # Extract the leading digits
  38         digits="$(echo "$file" | sed 's/\([0-9]*\).*/\1/')";
  39         # Zero-pad the digits
  40         padded_digits="$(printf "%0${max_digits}d" "$digits")";
  41         # Construct the new filename
  42         new_file="${padded_digits}${file#${digits}}";
  43         # Rename the file
  44         if [[ "$file" == "$new_file" ]]; then continue; fi;
  45         mv -n "$file" "$new_file"
  46         # declare -p file new_file; # debug
  47     done < <(list_files);
  48 }; # main program
  49
  50 main "$@";
  51
  52 # Author: Steven Baltakatei Sandoval
  53 # License: GPLv3+