Difference between bash pid and $$

Question

I\'m a bash scripting beginner, and I have a \"homework\" to do. I figured most of the stuff out but there is a part which says that I have to echo the pid of the parent bas

Answer 1

It'd be best to get well-acquainted with bash(1):

   BASHPID
          Expands to the process ID of the current bash process.
          This differs from $$ under certain circumstances, such
          as subshells that do not require bash to be re-
          initialized.
   [...]
   BASH_SUBSHELL
          Incremented by one each time a subshell or subshell
          environment is spawned.  The initial value is 0.

$BASHPID was introduced with bash-4.0-alpha. If you run bash --version you can find out what version of bash(1) you're using.

If you're going to be doing much bash(1) work, you'll also need the following:

• Greg's bash FAQ
• TLDP bash reference card