Question

Normally when a parameter is passed to a shell script, the value goes into ${1} for the first parameter, ${2} for the second, etc.

How can I set the default values for these parameters, so that if no parameter is passed to the script, we can use a default value for ${1}?

Answer 1

You can’t, but you can assign to a local variable like this: ${parameter:-word} or use the same construct in the place you need $1. this menas use word if _paramater is null or unset

Note, this works in bash, check your shell for the syntax of default values