# Example: zeropad.sh;
# zeropad.sh ".jpg";
# Input: arg1 str file extension of files to apply changes to
-# Version: 0.1.1
+# Version: 0.2.0
declare fext; # file extension
| 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="$1";
fi;
- # Find the maximum number of leading digits in the filenames of working dir
- max_digits="$(list_files | sed -e 's/[^0-9].*//' | awk '{ if(length > L) L=length } END { print L }')";
- # declare -p max_digits; # debug
+ 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 's/\([0-9]*\).*/\1/')";
+ 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" "$digits")";
+ padded_digits="$(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" "$new_file"
- # declare -p file new_file; # debug
+ mv -n "$file" "$new_file";
+ #declare -p max_digits file digits digits_nlz padded_digits new_file # debug
done < <(list_files);
}; # main program