System Command - Change Dir

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

Replies are listed 'Best First'.
Re: System Command - Change Dir by holli (Abbot) on Aug 25, 2008 at 07:16 UTC
Actually the directory is changed, but you don't notice because you are shelling out. That means your code starts a shell, changes the directory within that shell and then the shell exits. That's not what you want. Use the builtin function `chdir`. That changes the cwd of the running script. (see perlfunc) holli, /regexed monk/	[reply] [d/l] [select]
Re: System Command - Change Dir by tilly (Archbishop) on Aug 25, 2008 at 07:16 UTC
Short answer, use chdir and your problem goes away. You're not doing error checking as perlstyle indicates, and that hides additional errors. Here is a fuller explanation. The system command creates a new process that does something then exits. So if you have a system command that does a cd, the child process does a CD and goes bye bye. Which leaves the Perl process still in the original directory. Actually it is a little worse than that. You're using both backticks and system. So you execute the command using backticks, and then the return from that (an empty string) is passed to system. Which then fails but you don't notice because you're not doing any error checking. Anyways you need the changing directory to happen in the Perl process, and not in a temporary process that goes away. And that is why you have to use the built-in chdir instead.	[reply]
Re: System Command - Change Dir by lima1 (Curate) on Aug 25, 2008 at 07:18 UTC
You don't have to quote the slashes. But why don't you use the chdir function? Example from die `chdir '/usr/spool/news' or die "Can't cd to spool: $!\n"` [download]	[reply] [d/l]
Re^2: System Command - Change Dir by ganilmohan (Acolyte) on Aug 25, 2008 at 10:20 UTC
Thanks ALL It worked.	[reply]