xNightR00T File Manager

#! /usr/bin/perl

# usage: add-option OPTION
#
# Modify default boot option (resp. add it).
#
# OPTION is either of the form 'key=value' or 'key="value"' or just 'key'.

use strict;

my $file = "/etc/default/grub";

my $opt = shift;

my $opt_name = $opt;

if($opt_name =~ s/=("?).*//) {
  $opt =~ s/"/\\"/g;
}

exit 1 if $opt_name eq "";

open my $f, $file or die "$file: $!\n";
my @lines = (<$f>);
close $f;

my $changed = 0;

for (@lines) {
  if(/^(GRUB_CMDLINE_LINUX_DEFAULT)=(.*)/) {
    $changed = 1;
    my $key = $1;
    my $val = $2;

    $val =~ s/(^"\s*|\s*"\s*$)//g;

    $val =~ s/(^|\s)$opt_name=(\\"[^"]*\\"\s*)/ $opt / or
    $val =~ s/(^|\s)$opt_name((\s|$)|(=\S*\s*))/ $opt / or
    $val .= " $opt";

    $val =~ s/^\s+|\s+$//g;

    $_ = "$key=\"$val\"\n";
  }
}

exit 0 unless $changed;

open my $f, ">$file.pblnew" or die "$file.pblnew: $!\n";
print $f @lines;
close $f;

rename "$file.pblnew", $file;