System command & warnings

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I have code such as that below and it works fine unless the command "my_command" is not found. Then it spits out an error such as:

Can't exec "my_command": No such file or directory

How can I print my own error message instead of the one above if the command is not found? I realize I could turn off warnings, but I don't really want to do that.

#!/usr/bin/perl -w
use strict;
my $output=`my_command -v`;
[download]

Comment on System command & warnings Download Code

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Re: System command & warnings by blue_cowdawg (Monsignor) on May 13, 2004 at 14:18 UTC
How can I print my own error message instead of the one above if the command is not found? How about something like this: : : : much hand waving.... : my $output=""; eval " $output=`my_command -v`; "; if ($@){ print "it broke!\n"; } else { : whatever... } [download] disclaimer: completely untested and I don't know what's in "my_command".	[reply] [d/l]
Re: Re: System command & warnings by ambrus (Abbot) on May 13, 2004 at 17:57 UTC
An eval-block is probably better here than an eval-string.	[reply]
Re: System command & warnings by ysth (Canon) on May 13, 2004 at 16:11 UTC
use warnings; my $output = do { no warnings "exec"; `my_command -v` }; [download] Caveat: I've had funky stuff happen sometimes combining "no warnings" with -w; haven't gotten around to tracking it down yet, but I'd recommend useing "use warnings" rather than -w.	[reply] [d/l]
Re: System command & warnings by Taulmarill (Deacon) on May 13, 2004 at 14:25 UTC
i didn´t find a way using backticks. but i have a solution whith open: `my $output; open PROG, "\|my_command -v" or die "can´t exec my_command \n"; while ( <PROG> ){ $output .= $_; }` [download]	[reply] [d/l]