Read and strip with regex

Large fill need stripping

[StanTheMan]

I have a large file of test that cann't be imported into a database but I want to strip all the postcode's out of the file, I have tried below but it strips the whole line out. But I want just the variable i.e postcode in a seperate file.

#!/usr/bin/perl
open(MYINPUTFILE, "<input.log");
my(@lines) = <MYINPUTFILE>;
my($line);
foreach $line (@lines) {
$username =~ "/\d{3}/";
print $username;
print "\n";
}
close(MYINPUTFILE);

Can anyone help me?

[sugarkane]

What format is the post code stored as? ie 5 digits, or combination of letters and digits etc..

And how is each line formatted - comma seperated, space seperated, or...?

[StanTheMan]

I have the postcode regex sorted but when I output it, it returns the whole line, rather than just the post code variable.

[Storyteller]

With the syntax you're using for regexp operation, variable $username gets assigned either undef or 1, depending on whether regexp matches. I'm not sure this is what you want, is it?

[StanTheMan]

No I want to output just the postcode that is being stripped from the code, not the full line.

How would I go about doing this with the code above?

[tschild]

try

if ($line =~ m/(regexp_matching_a_postcode)/) {print "$1\n"}; 

or, if one line may contain more than one postcode,

while ($line =~ m/(regexp_matching_a_postcode)/g) {print "$1\n"}; 

[StanTheMan]

Many Thanks tschild

Saved again by Webmasterworld. Thanks again.