Question

int main(int argc, char **argv)
{
  char input[150];
  char change[2] = "cd";
  char *directory;

  while(1) {
      prompt();
      fgets(input, 150, stdin);

      if(strncmp(change, input, 2) == 0) {
          directory = strtok(input, " ");
          directory = strtok(NULL, " ");

          printf(directory);
          chdir(directory);
          perror(directory);

      }

      if(feof(stdin) != 0 || input == NULL) {
          printf("Auf Bald!\n");
          exit(3);
      }
  }
}

when i start this and type in “cd test” i get “no such file or directory”. But there is the directory “test”.

Runs on Arch Linux.

Answer 1

From the man page:

fgets() reads in at most one less than size characters from stream and
stores them into the buffer pointed to by s. Reading stops after an
EOF or a newline. If a newline is read, it is stored into the buffer.

The problem is there’s a newline character '\n' at the end of your string that you got from fgets(), you need to remove it:

fgets(input, 150, stdin);
input[strlen(input)-1] = '\0';

Also:

char change[2] = "cd";

That should be change[3], it’s 2 (for “cd”) + 1 for the NULL terminator '\0' which is automatically placed for you.

Then it should work.

EDIT:

A different alternative is to change the strtok() call such that:

directory = strtok(NULL, " \n");

This will work if the user enters the string via the enter key or via the EOF (ctrl + d on Linux) character… I’m not sure how likely the second is for a user to do… but it couldn’t hurt!