Programming

$ cat process.c
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)
{
    FILE *proc, *out;
    char buffer[1024];

    proc = popen("/bin/ls /", "r");
    out = fopen("output.txt", "w");

    while (!feof(proc)) {
        fgets(buffer, 1024, proc);
        fprintf(out, "%s", buffer);
    }
    fclose(out);
    pclose(proc);

    return 0;
}
$ ./process
$ cat output.txt
bin
boot
dev
etc
home
lib
lost+found
media
mnt
opt
proc
root
sbin
srv
sys
tmp
usr
var
var

ls -l /

shell = popen("./shell_script", "r")

//and then comes the reading

$ ./process
$ cat output.txt
bin
boot
dev
etc
home
lib
lost+found
media
mnt
opt
proc
root
sbin
srv
sys
tmp
usr
var
var
insgesamt 0
lr-x------ 1 pludi users 64 30. Apr 13:12 0 -> pipe:[1498244]
l-wx------ 1 pludi users 64 30. Apr 13:12 1 -> /tmp/testbed/output.txt
l-wx------ 1 pludi users 64 30. Apr 13:12 1 -> /tmp/testbed/output.txt