f

        #!/usr/bin/perl

        my $field = shift or usage();
        $field -= 1 if $field > 0;

        while (<>) {
                chomp;
                my @f = split;
                print $f[$field], "\n";
        }

        sub usage {
                print STDERR "$0 fieldnumber\n"; 
                exit 1;
        }

• The $field -= 1 is so that f 1 emits the first column of input

• But why if $field > 0?

• That's so that this works:

        ls -l | grep 'May 22' | f -1

• f -1 emits the last column of input

• All this is inconsistent

• In particular, f 0 and f 1 do the same thing

• That's OK

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Copyright © 2005 M. J. Dominus