Update indent of files from 4 to 2 spaces

update-indent.sh

#!/bin/bash
#
# Usage:
#
#   Find all files
#
#     ls -1 $PWD/*.js > files.txt
#
#   Run script
#
#     ./update-indent.sh files.txt > files-output.log
#
# Based on https://superuser.com/a/860725/28191

while read filename; do
    if ! [[ -r "$filename" ]]; then
        echo "Skipping '$filename' because not readable"
        continue
    fi
    tempfile="$(mktemp)"
    if perl -ne '$_ =~ s|^((    )+)|"  " x (length($1)/4)|eg; print $_' < "$filename" > "$tempfile"; then
        # Uncomment if you want the original file
        #mv "$filename" "$filename".orig
        mv "$tempfile" "$filename"
        echo "Success processing '$filename'"
    else
        echo "Failure processing '$filename'"
    fi
done < "$1"