G'day cryion,

Welcome to the Monastery.

"But I have no way around using regex at the moment."

Using a regex to parse XML is generally a poor choice. Why do you have no way around this?

On the basis that you must use a regex, there is a distinct disconnect between the code and data you've posted and the regex you say doesn't work.

Parsing your XML code, line by line, with the regex you've shown (i.e. 'file:(.*?).xml'), captures one piece of data:

/path/to/some/file
[download]

Had you used different paths, such that you could see which path was being matched, you'd know that 'file:/path/to/some/file.mxf' ("the very first occurence of the file: string") was not matched at all. Consider this test:

#!/usr/bin/env perl -l

use strict;
use warnings;

my $re = qr{file:(.*?).xml};

while (<DATA>) {
    print $1 if /$re/;
}

__DATA__
<xml>
<info>
<file>file:/path/to/someA/file.mxf</file>
</info>
<info>
<file>file:/path/to/someB/file.xml</file>
</info>
</xml>
[download]

Output:

/path/to/someB/file
[download]

So, you're matching the right path, but not capturing all of it.

A '.' in a regex matches any character (except newline), so you really need '\.xml', not '.xml'. The closing parenthesis needs to be after '\.xml' to capture to whole pathname.

Making those changes:

#!/usr/bin/env perl -l

use strict;
use warnings;

my $re = qr{file:(.*?\.xml)};

while (<DATA>) {
    print $1 if /$re/;
}

__DATA__
<xml>
<info>
<file>file:/path/to/someA/file.mxf</file>
</info>
<info>
<file>file:/path/to/someB/file.xml</file>
</info>
</xml>
[download]

Gives this output:

/path/to/someB/file.xml
[download]

Which is what you state you wanted: "the whole path to the xml file".