[ILUG] Re: Need Help with Perl Script

[Dave O Connor]

Someone called ilug-admin at linux.ie said on Tue, May 02, 2000 at 03:06:59PM +0100:
> Tina Marie's [TinaDp6 at netscape.net] 22 lines of dribble included:
> > 
> > 
> > I need to have the number of users printed out within my perl script.
> > 
> >   I know the UNIX command is w -h | wc -l
> That doesn't work if users are logged in multiple times. 
> w | awk '{print $1}' | sort | uniq | wc -l
> (sort -u saves a pipe on some systems)
> 
> >   But how do I get it to print out like the sample below?
> > 
> > 
> >   There are 7 users logged on the system.
> This sounds more of a shell scripty way of doing things than actually needing
> to do it in perl. However if what you're looking for is something like
> 
> #!/usr/bin/perl
> $blah = system("w | awk '{print $1}' | sort | uniq | wc -l");
> print "There are $blah users logged on";
> 
That'd ouput the return value from that nasty shell command, which you don't
really want. A slightly more efficient (resourcewise, anyway) would be
something like:

sub num_users
{
	open(USERS,"/usr/bin/users|");

	my $users = <USERS>;

	close USERS;

	my @userlist = split(/\s+/,$users);

	my @uniqlist;

	foreach (@userlist)
	{
		if (!grep($_, at uniqlist))
		{
			push(@uniqlist,$_);
		}
	}

	return scalar @uniqlist;
}

	- DoC, the bored.