#!/usr/bin/perl -w
use strict;
my $fname;

open FNAMES,"</var/tmp/flist";
while ( $fname = <FNAMES> )
{
        chomp ($fname)
# Does the string start with an "s"?
        if ( /^$fname/ eq "s" )
        {
        # how do I do the substitution??
        printf "hello\n";
        }
}