如何使用execlp使'ls -l $ pwd'工作？

Question

I have read the following answer from @nos on how to implement the execlp command but I am unable to run the same specifically for ls -l $pwd using execlp. I have tried both execlp("ls","ls", "-l", "$pwd", (char *)NULL); and execlp("ls","ls", "-l", "pwd", (char *)NULL); but nothing seems to work. Any directions in this thought process would be really helpful

Thanks.

Answer 1

Those $... variable belongs to shell , not the OS internal. When in shell you type such variables, shell will transform them to their actual value and then call system call.

In C program, you need to do it by yourself:

#include <unistd.h>

int main() {
    char *cwd = getcwd(NULL, 0);
    execlp("ls","ls", "-l", cwd, (char *)NULL);
}

getcwd() will give you the current directory.