ipsedixit

05 February 2022

Bash shell has some usefull special parameters:

$* Expands to the positional parameters
$# Expands to the number of positional parameters in decimal
$? Expands to the exit status of the most recently executed foreground pipeline
$$ Expands to the process ID of the shell
$! Expands to the process ID of the job most recently placed into the background

References

More information could be found in GNU documentation