Change directory with popen

Question

I'm able to use popen to run just about any program, but apparently not cd:

#include <stdio.h>
void main() {
    FILE *fp = popen("cd", "w");
    pclose(fp);
}

I'd expect that to change directory to home but nothing happens. Changing to "r", or changing to e.g. "cd ~", "cd /", does not help. Using system has about the same result, i.e. works for anything but cd. So how is it done? The answers here don't work for me. Thank you.

To change working dir of the process use `chdir()` http://man7.org/linux/man-pages/man2/chdir.2.html — metamorphling, Jul 06 '17 at 04:20
I think my answer is given in the question "linked" by @ephemient, which I hadn't seen. Thanks. — Erik Vesterlund, Jul 06 '17 at 04:26

score 0 · Answer 1 · answered Jul 06 '17 at 04:17

0

cd is generally a shell internal command, NOT an executable.

Even if it were, in general no process can change another process's working directory, so it would change the cwd for the "cd" process and then upon exit it'd be gone.

answered Jul 06 '17 at 04:17

Dale

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`cd` is practically always a shell builtin. Can you name any implementation where it is not? – Basile Starynkevitch Jul 06 '17 at 04:19
1

No, but I don't know every implementation under the sun so I went with a safer answer of "generally" instead of "always." – Dale Jul 06 '17 at 04:42

Change directory with popen

1 Answers1