$ cat test1.pl
#!/usr/bin/perl

$string = 'test';
$inputs = 'test.txt';

open(TABLE, $inputs) or die "can't open $inputs.\n";

while ( $line = <TABLE> ) {
  if ( $_ =~ $string ) {
    print $_;
  }
}

close(IN);
$ cat test.txt
test
tst
$