You may wish to look at the getpwnam() function to get the directory entry for you, such as in the following example:

#!/usr/bin/perl -w

use strict;

(
    my $name,
    my $passwd,
    my $uid,
    my $gid,
    my $quota,
    my $comment,
    my $gcos,
    my $dir,
    my $shell,
    my $expire
  )
  = getpwnam('user');

# Insert '(undef)' if variable is undefined.
foreach my $x (
    \$name,    \$passwd, \$uid, \$gid,   \$quota,
    \$comment, \$gcos,   \$dir, \$shell, \$expire
  )
{
    ${$x} = '(undef)' unless ( defined( ${$x} ) );
}

printf
  <<OUTPUT, $name, $passwd, $uid, $gid, $quota, $comment, $gcos, $dir,
+ $shell, $expire;
getpwnam() OUTPUT:
    name:       %s
    passwd:     %s
    uid:        %s
    gid:        %s
    quota:      %s
    comment:    %s
    gcos:       %s
    dir:        %s
    shell:      %s
    expire:     %s
OUTPUT
[download]

According to the docs for the function, a null list would be returned if the user did not exist.

Hope that helps.