perl.pl

#!/usr/bin/perl
use warnings;
use strict;

# args: login shell
sub change_shell {
	my $username = shift;
	my $shell = shift;
	my @command = ("chsh", "-s ".$shell, $username );
	system(@command) or print STDERR "Failed to chsh";
}

# args login gid
sub change_group {
	open PASSWD, '</etc/passwd' or die $!;
	
	my $uid = 1000;
	
	while (<PASSWD>) {
		chomp;
		my @line = split(/:/);
	
		if ($line[2] > $uid) {
			$uid = $line[2];
		}
	
	}
	close(PASSWD);
	return $uid+1;
	
}


# This function generates random strings of a given length
sub generate_password {
	
	my $length_of_randomstring = shift; 

	my @chars=('a'..'z','A'..'Z','0'..'9','_','!','@','#','$','%','^','&','(',')','-','=','+');
	my $random_string;
	foreach (1..$length_of_randomstring) 
	{
		$random_string .= $chars[rand @chars];
	}
	return $random_string;
}



# Follows unix convention: free uid is higher not taken uid
sub find_free_uid {
	open PASSWD, '</etc/passwd' or die $!;
	
	my $uid = 1000;
	
	while (<PASSWD>) {
		chomp;
		my @line = split(/:/);
	
		if ($line[2] > $uid) {
			$uid = $line[2];
		}
	
	}
	close(PASSWD);
	return $uid+1;
}

sub uid_exists {
	my $uid = shift;

	open PASSWD, '</etc/passwd' or die $!;
	
	while (<PASSWD>) {
		chomp;
		my @line = split(/:/);
	
		if ($line[2] == $uid) {
			return 1;
		}
	}
	close(PASSWD);
	return 0;
}


my @args = ("ls", "-la");


print find_free_uid();