Shell Script Parameters
A bash shell script have parameters. These parameters start from $1 to $9.
When we pass arguments into the command line interface, a positional parameter is assigned to these arguments through the shell.
The first argument is assigned as $1, second argument is assigned as $2 and so on…
If there are more than 9 arguments, then tenth or onwards arguments can’t be assigned as $10 or $11.
You have to either process or save the $1 parameter, then with the help of shift command drop parameter 1 and move all other arguments down by one. It will make $10 as $9, $9 as $8 and so on.
Shell Parameters
| Parameters | Function |
|---|---|
| $1-$9 | Represent positional parameters for arguments one to nine |
| ${10}-${n} | Represent positional parameters for arguments after nine |
| $0 | Represent name of the script |
| $∗ | Represent all the arguments as a single string |
| [email protected] | Same as $∗, but differ when enclosed in (“) |
| $# | Represent total number of arguments |
| $$ | PID of the script |
| $? | Represent last return code |
Example:
Look at the above snapshot, this is the script we have written to show the different parameters.
Look at the above snapshot, we have passed arguments 1, 5, 90. All the parameters show their value when script is run.