Special variables in shell

Special variable $0 Script Name in shell $1 Location Parameter #1 $2-$9 location parameter #2-#9 $ {10} location parameter #10 $ # Number of location parameters "$ *" All location parameters (as a single string) "$ @" All location parameters (each as an independent string) $ {#*} Number of command line parameters passed to the script $ {#@} Number of command line parameters passed to the script $? Returned value $ PID of the script $-flag passed to the script (use set) $ _ the last parameter of the previous command $! ID of the process (PID) of the last job running in the background)