Do you know about backticks?

Here's a silly example to get you started:

#! perl -slw
use strict;

die "You must supply an extension" unless @ARGV;

for ( @ARGV ) {
    my( $extention, $type ) = split '=', `assoc $_ 2>nul`;
    warn "No association was found for extension '$_'" and next
        unless defined $type;
    chomp $type;

    my( undef, $cmd ) = split '=', `ftype $type 2>nul`;
    warn "No command was associated with type '$type'" and next
        unless defined $cmd;
    chomp $cmd;

    print "Extension '$_' is associated with type '$type' "
    .     "\n\tand the command: '$cmd'";
}
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And an example of using the above code:

c:\test>AssocFtype.pl .pl .doc
Extension '.pl' is associated with type 'Perl'
        and the command: '"c:\perl\bin\perl.exe" -sw "%1" %*'
Extension '.doc' is associated with type 'OpenOffice.org.doc'
        and the command: '"C:\Program Files\OpenOffice.org 2.2\program
+\soffice.exe" -o "%1"'
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