Homework & Coursework Questions

Very good!

For your Part A: have a look at the wc command. You might find its man page as interesting as the one of "find" (which you seem to have enjoyed, telling from your script).

Just a few suggestions:

Shell programming is programming, so all the rules for proper programming technique apply. This means in your case that a function should always give an explicit return value, even if this is not necessary in your case. Furthermore, it is good style to copy the positional parameters into local variables, which douments them as a side effect:

Code:

PastXDays ()
{
     typeset -i threshold=$1

     find . -mtime -$threshold

     return $?
}

Then there is the handling of arithmetic operations in the main script. The way you did it is absolutely correct and in fact the old way to do it. But modern shells all have at least integer arithmetics built in, so there is no need any more to use expr. Have a look in the man page of your shell about "(( .. ))" and notice that surrounding spaces are necessary:

Code:

(( neg2pos = 10 ))
while [ $neg2pos -ge 0 ] ; do
     echo "neg2pos is now: $neg2pos"
     (( neg2pos -= 1 ))
done

Again, the main part of the script should be left with "exit <int>", which will set the errorlevel of the script after returning to the OS. It is good style to give this some meaningful value, usually "0" for successful completion and values greater than 0 for all kinds of malfunctions/errors.

I hope this helps.

baunin