What does mean $$ or $! in bash?
bash, shell
Solution
Actually, these variables were inherited by bash from the Bourne shell.
`$$` means current PID.
`$!` is the PID of the last program your shell ran in the background (e.g. `myprog &`)
Here is a list of shell variables:
- http://unixhelp.ed.ac.uk/scrpt/scrpt2.2.2.html
Problem
It's kind of easy question but I didn't find any information. What does mean `$!` or `$$` in bash? For example: `ps -p $!` or `pstree $$`?