executing a command in perl

[Neo]

I am trying to use perl to unzip & untar a file using the system command.
Is there any way I can determine if this worked successfully?
I am using

Code: Select all

$result = system("gunzip $fileName");

but am not sure if there is a better way?

[Solar]

Uh... Perl's system() is not exactly broken, but not easy to handle either. Most importantly, what gets returned by system() is not the return code of the command executed:

• -1 means the command failed to start, "inspect $! for the reason";

• if the process terminated normally, the 8 low-order bits of the return value are 0, the 8 high-order bits contain the exit() value (i.e., the return code of the command executed);

• if the process terminated due to a signal, the 8 high-order bits contain 0, and the 8 low-order bits contain the signal value;

• if the process was stopped, the low-order bits contain WSTOPFLG, and the high-order bits contain the signal that caused the process to stop.

Have fun...

[Neo]

Uh... Perl's system() is not exactly broken, but not easy to handle either. Most importantly, what gets returned by system() is not the return code of the command executed:

Is there any alternative to executing commands from within perl?

[Solar]

Backticks?

Or you can do:

open( CMD, "foo |" )

to execute foo, and reading its output. AFAIK, after closing the pipe $? contains the same "return code" as system().

[Candy]

perl is a WORN language - Write Once Read Never

What's the reasoning behind that open statement?

[Solar]

No, absolutely correct. foo gets executed by the shell, output gets piped to the file handle.

You shouldn't use this style of file handle; there's something called "anonymous file handles" where you assign a file handle reference to a variable or somesuch... I don't use Perl except for quick&dirty, so I never got into the fine print much.