Changes the number of indent spaces.

indent.pl

#!/usr/bin/env perl
use strict;
use warnings;
use utf8;
use Getopt::Long qw{:config auto_help};
use Pod::Usage qw{pod2usage};

GetOptions(\my %opt, qw{in=i out=i}) or pod2usage(1);

$opt{in} ||= 4; # the default number of input indent spaces

pod2usage(1) if !exists $opt{out};

while (<>) {
    if (/\A([ ]+)([^ ].*)\z/s) {
        my $length   = length $1;
        my $level    = int($length / $opt{in});
        my $reminder = $length % $opt{in};
        print ' ' x ($opt{out} * $level);
        print ' ' x $reminder;
        print $2;
    }
    else {
        print;
    }
}

__END__

=head1 SYNOPSIS

    $ indent.pl -i=8 -o=4 source.c

=cut