Shell Programming and Scripting

So one never passes the local variables to the function. Is that correct, we pass only the arguments we want to be passed.

---------- Post updated at 04:44 PM ---------- Previous update was at 04:40 PM ----------

That was a superb example agama. You said it all.

There is nothing that would stop a function from being called and where the 'local' variables are also passed, but it is likely that they will be ignored by the function. The demo() function could have been invoked with (a,b,1,2) but that would not have changed the result as the function did not expect the variables c and d to contain useful information and assigned values before using them in the printf().

Glad the example helped.

How does the function know c and d are local? From what I understand now, all variables passed to the function are local, even 'a' and 'b'. Depends whether we use 'a' and 'b' for some calculation. Does one actually need to put a tab to recognize whether variables are local or not?

You are correct, all variables that appear in the function declaration are local. The tab, or extra white space, is only to help humans who come along and maintain your programme. It's an easy signal that everything to the right of the extra space is just a local variable and that the function is not expecting to have those values passed in.

I've been using awk for the last 15 years or so, and I still get tripped up now and again because I forget to put a local variable in the header. Not one of awk's easier concepts to explain or understand; you've done well with it.

Thanks.