Question

int status=0;
int PID = fork();
if(PID == 0)
{
   char *path = strcat(pathToken,strcat("/",command));
   printf("path: %s\n",path);
   execl(path,command,"-l",NULL);
}
else if(PID>0)
{
   printf("pid: %d. ",PID);
   printf("I'm parent process\n");
   wait(&status);
}

Output:

pid: 20027. I'm parent process

Why it doesn’t enter if(PID==0)?

Answer 1

You are trying to modify a string literal in:

strcat("/",command)

which leads to undefined behavior.

The declaration for strcat is:

char * strcat ( char * destination, const char * source );

And it appends a copy of the source string to the destination string.