picard:~/tmp [21:23:31]$ ls
file1  file2
picard:~/tmp [21:23:37]$ cat file1
line1
line2
picard:~/tmp [21:23:42]$ cat file2
line1
line2
picard:~/tmp [21:23:44]$ cat ../domk.pl
#!/usr/bin/perl

use strict;
use warnings;

while (<>) {
    chomp;
    print collect( $_ );
}

sub collect {
    local @ARGV = @_;
    join '', <>;
}

__END__
picard:~/tmp [21:23:53]$ ls file? | perl ../domk.pl
Can't open file1: No such file or directory at ../domk.pl line 13, <> line 3.
file2