man Filter::exec (3): exec source filter

SYNOPSIS

use Filter::exec qw(command parameters) ;

This filter pipes the current source file through the program which corresponds to the "command" parameter.

As with all source filters its scope is limited to the current source file only. Every file you want to be processed by the filter must have a

    use Filter::exec qw(command ) ;

near the top.

Here is an example script which uses the filter:

    use Filter::exec qw(tr XYZ PQR) ;
    $a = 1 ;
    print "XYZ a = $a\n" ;

And here is what it will output:

    PQR = 1

You should be very careful when using this filter. Because of the way the filter is implemented it is possible to end up with deadlock.

Be especially careful when stacking multiple instances of the filter in a single source file.

Paul Marquess

11th December 1995.