You can replace system("clear") by print "\e[H\e[2J"; or use a Term::..CPAN module.

Replacing the calls to (e)grep is possible but I guess, also slower. See glob or File::Find for methods to find all those group and password files. A simple grep emulation for a single file could be:

sub my_grep {
 my ($filename, $re) = @_;
 open my $fh, '<', $filename or die "cannot open $filename - $!";
 my @matching_lines = grep /$re/, <$fh>;
 close $fh or die "cannot close $filename - $!";
 return @matching_lines; # might need further chomping?
}

my $group_re = qr{^samplegrp:};
foreach my $grpfile (glob "group/server*.grp") {
  print "$grpfile: ", my_grep($grpfile, $group_re), "\n";
}
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That's for the replacement of sytem calls - as requested.

Alternatively, If those files fit into memory, you could read them once and then run multiple searches across them - but finally, a database might serve better in the long term...