How does a Linux/Unix Bash script know its own PID?

Question

I have a script in Bash called Script.sh, and it needs to know its own PID (i.e. I need to get PID inside the Script.sh )

Any idea how to do this ?

Answer 1

In addition to the example given in the Advanced Bash Scripting Guide referenced by Jefromi, these examples show how pipes create subshells:

$ echo $$ $BASHPID | cat -
11656 31528
$ echo $$ $BASHPID
11656 11656
$ echo $$ | while read line; do echo $line $$ $BASHPID; done
11656 11656 31497
$ while read line; do echo $line $$ $BASHPID; done <<< $$
11656 11656 11656