### this file is called regex.pl
my $testVar;
$testVar = "January";

### read this file
open(FH,"<regex.pl") or die "cannot open file";
my @myself = <FH>;
close(FH);
 
### make $pattern: $testVar
$myself[2]=~/([^ ]+)/;
my $pattern = $1;
print "Pattern: $pattern\n";

### print lines with this pattern
for(@myself)
{
  print if /$pattern/;
}