Question

I have a script and I am trying to elimate bad practices using perlcritic.

One line I have is as follows:

open(my($FREESPCHK), $cmdline ) || &zdie($MSG_PASSTHRU,"Error checking free space of file system.");

This gives this error:
Two-argument “open” used at line xxx, column x. See page 207 of PBP. (Severity: 5)

Any ideas on how to fix it?

Answer 1

To make Perl Critic shut up, but do no real good at all, just modify the code to:

open(my $PIPE_FROM_FREESPCHK, "-|", $cmdline)
    || zdie($MSG_PASSTHRU, "Error checking free space of file system.");

Note however that this is absolutely no better in any regard whatsoever from the far more obvious:

open(my $PIPE_FROM_FREESPCHK, "$cmdline |")
    || zdie($MSG_PASSTHRU, "Error checking free space of file system.");

Because you are not separating out your tokens for calling exec directly. That would look more like this:

open(my $PIPE_FROM_FREESPCHK, "-|", $cmd_name, @cmd_args)
    || zdie($MSG_PASSTHRU, "Error checking free space of file system.");

The question is whether you are running a shell command or just exec’ing something. If your free check is something like df . 2>/dev/null | awk ...., then you need the full shell. If it is just df, then you don’t.