Arguments for Bash Scripts are denoted $0-$9, which are reserved placeholder variable names for arguments passed to the script.
We can pass 9 variables as input, since the first argument $0 is reserved for the script itself.
How the arguments are assigned when a script is called can be illustrated with:
./script.sh ARG1 ARG2 ARG3 ... ARG9
$0 $1 $2 $3 ... $9