Hello wise monks,

Here a little code snippet which opens the command "dir" for reading and then prints the output of "dir".

#!/usr/bin/perl

use strict;
use warnings;

open(my $CMD, "dir |") || die $!;
while( <$CMD> )
{
    print "$_";
}

close($CMD);
[download]

Now I tried the same, but with a not-existing command "dira".

#!/usr/bin/perl

use strict;
use warnings;

open(my $CMD, "dira |") || die $!;
while( <$CMD> )
{
    print "$_";
}

close($CMD);
[download]

Of course my goal would it be that the open command dies the program because the command "dira" does not exist.

But I get here on my german computer the following output:

Der Befehl "dira" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.
[download]

So my question is, how can I check when I open a process, if the command really exists?

Of course I could check if the output is "Der Befehl ...". But this is then dependent of the language, the OS, ... . In other words this would be a very specific solution.

Another possibility would be to loop through all pathes in the environment variable PATH and then checking if the command exists.

Unfortunately I do not have more ideas. That's the reason why I ask you.

Thank you for your help.

Greetings,

Dirk

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.