Using cd command with fork in c

问题

Is it possible to change around directories using the fork command? Without going too much into my code I have the following:

childpid = fork();

if (childpid >= 0)
{
    if (childpid == 0)
    {   
        ret = execvp(argv[0],argv);
        exit(ret);    
    } else {

          waitpid(childpid,&status,0);
          ret = WEXITSTATUS(status);
    }
}

The above works fine when I'm entering basic command like ls, pwd, etc.. Is it possible to implement a way to use the cd function? I can type the command cd .. but it doesn't do anything.

For example if my program is in /Users/username/Desktop/ I would like to use commands such as cd .. to go into /Users/username/ or be able to go straight into /Users

I've seen some stuff about chdir but I'm not sure exactly how it works/how to use it.

回答1:

As you mentionned chdir is the best way to change the working directory of the current process, a shell command cd would only change the working directory of of the process running the command ( and not the parent process ) as fork would create a new process.

for chdir usage you could try :

#include <stdio.h>
#include <unistd.h>
int main() {
    char cwd[4096];
    fputs(getcwd(cwd,4096),stdout); // will print the current working directory
    fputs("\n",stdout); 
    chdir("/"); // change directory
    fputs(getcwd(cwd,4096),stdout); // print new working directory
    fputs("\n",stdout);
}

来源：https://stackoverflow.com/questions/38579233/using-cd-command-with-fork-in-c

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Linux