bash build-in variables

There are some fancy build-in variables in bash that I picked up from others’ scripts. They start with a dollar sign. Guess I’ll take some notes. (mostly stole from SO)[https://stackoverflow.com/questions/5163144/what-are-the-special-dollar-sign-shell-variables]

• $# number of arguments

• $@ and $* return all the parameters, but answer on SO

$@ behaves like $* except that when quoted the arguments are broken up properly if there are spaces in them.

• $? was last command successful?

• $0 $1 $2 ... positional arguments, $0 gives the

• $# number of positional parameters ($0 excluded)

• $- current options set for the shell

• $$ pid of the current shell

• $_ most recent parameter (probably rarely used)

• $IFS field separator