Reputation: 21921
What is the meaning of $$
in KornShell? I guess it is associated with the process ID, but I want to know its exact meaning.
Upvotes: 8
Views: 4570
Reputation: 78155
$$
is the process id of the ksh process itself; $PPID
is the process id of its parent.
Here's the ksh (93) documentation for special parameters (it's after the fold). Same info for ksh88.
Upvotes: 6
Reputation: 3144
It is used for making temporary names with the process id. Say you need a file name but that name needs to be unique to the process you are in - so if more than one person runs the same ksh script they will not step on each other.
$$ is in bash, sh and other UN*X shells.
Upvotes: 2