Question

Possible Duplicate:
What does $$ mean in the shell?
What are the Special Dollarsign Variables (Possibly bash Only)?

I am new to linux environment. I am dealing with a particular script that has a command like this

ps -p $$

-p should follow a process id but I don’t understand what $$ means. \
Could some linux gurus shed light on it ? isit a var where is it coming frome etc.,,

Thanks

Answer 1

The special $$ variable evaluates to the current process’ PID (process ID) — it is an integer number; it’s not listed by env as it’s not an environment variable. It’s a special built-in variable provided by BASH.