could not get exec and sytem to work

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

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Re: could not get exec and sytem to work by SuicideJunkie (Vicar) on Aug 19, 2014 at 19:59 UTC
Also notable, is that you don't want to create a child, have the child change its current directory, and then kill the child. That has no effect on your own current directory. See chdir instead.	[reply]
Re: could not get exec and sytem to work by McA (Priest) on Aug 19, 2014 at 18:50 UTC
Hi, let me cite the documentation to `exec`: The exec function executes a system command and never returns ... This should explain what you get. You never get to your second `exec` line. Regards McA	[reply] [d/l] [select]
Re: could not get exec and sytem to work by Laurent_R (Canon) on Aug 19, 2014 at 20:50 UTC
The best solution is to use the already mentioned `chdir` Perl built-in to get into the right default directory. But if you want to do it in shell, you could issue two shell commands within the same `exec` or `system` shell command string, for example; `my $home='~/bin/MIReNA-2.0'; system("cd $home; ./MIReNA.sh");` [download] An example Perl one-liner on my system: `$ perl -e ' exec "cd ./Matt; ls -l"' total 11756 drwxr-xr-x+ 1 Laurent None 0 27 juin 19:26 appartement -rwxr-xr-x 1 Laurent None 12038144 27 juin 22:27 appartement.tar` [download] In the latest example above, I used `exec` because I did not care that the program would die immediately after having displayed the content of the directory. I would use `system` if I wanted the Perl program to do other things after having run the shell command. And if I wanted to retrieve the data in Perl (which is probably the most common use of shelling out calls to the OS), say to format the output of the ls command with line numbers, then I would use backticks instead of `exec` or `system`: $ perl -E ' my @content = `cd ./Matt; ls -l`; print ++$i, ": $_" for +@content' 1: total 11756 2: drwxr-xr-x+ 1 Laurent None 0 27 juin 19:26 appartement 3: -rwxr-xr-x 1 Laurent None 12038144 27 juin 22:27 appartement.tar [download]	[reply] [d/l] [select]
Re: could not get exec and sytem to work by Anonymous Monk on Aug 19, 2014 at 20:31 UTC
Your post title says, "could not get exec and sytem to work", but your code doesn't show any use of system. Could you show the code that fails with system, and provide the error messages? "could not run properly" is not enough for us to help you. Please see How do I post a question effectively?.	[reply]