use strict;
use warnings;

my $inFile = q{spw623147.txt};
open my $inFH, q{<}, $inFile
   or die qq{open: $inFile: $!\n};

while ( <$inFH> )
{
    if ( m{\A\.rem} )
    {
        print qq{  Comment Line: $_};
        next;
    }
    if ( m{\A\.declare\s+(\S+)} )
    {
        print qq{     Data Line: $_};
        print qq{   Variable is: $1\n};
        next;
    }
    print qq{Not recognised: $_};
}

close $inFH
   or die qq{close: $inFile: $!\n};