Re^3: Opening not-existing command

This form of open starts a child process. The return result is the child process ID. Thus, your open(...) || die ... will show the error if the child can't be created. You need to check $? to check for errors from the child. See this for an example of checking for errors in this situation.

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Re^4: Opening not-existing command - Error Handling by Dirk80 (Pilgrim) on Aug 17, 2011 at 12:37 UTC
Thanks. You are right. Examining `$?` helps to know if the child process executed correctly or not. Here my sample code: `eval { open my $pipe, "perl --version \|"; my @res = <$pipe>; close $pipe; }; print "Exit Status: " . ($?>>8);` [download] If I use the not existing command "perl2 --version" then I get the following error message and the exit status 1. `Der Befehl "perl2" ist entweder falsch geschrieben oder konnte nicht gefunden werden. Exit Status: 1` [download] If I use an existing command like "perl --version" then I get the exit status 0 and no error message: `Exit Status: 0` [download] Problem of course is that I then know the error not directly after the `open`, but only when the child process exited, that means after the `close`.	[reply] [d/l] [select]

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Re^4: Opening not-existing command - Error Handling
by Dirk80 (Pilgrim) on Aug 17, 2011 at 12:37 UTC

Thanks. You are right. Examining $? helps to know if the child process executed correctly or not.

Here my sample code:

eval
{
    open my $pipe, "perl --version |";
    my @res = <$pipe>;
    close $pipe;
};

print "Exit Status: " . ($?>>8);
[download]

If I use the not existing command "perl2 --version" then I get the following error message and the exit status 1.

Der Befehl "perl2" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.
Exit Status: 1
[download]

If I use an existing command like "perl --version" then I get the exit status 0 and no error message:

Exit Status: 0
[download]

Problem of course is that I then know the error not directly after the open, but only when the child process exited, that means after the close.

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