Shell Programming and Scripting

Does success return 1 and failure 0 with these when using the if statement?

Yes you would need to check like this, but you would need to use a single =-sign for proper syntax. If you put double quotes around the variable, then you do not need to initialize it first:

Code:

if [ "$hasArgument" = 1 ]; then
   ...
fi

Like we've been telling you all along, shell does not have boolean. Even program return codes aren't boolean.

They return zero for success, and nonzero for anything else. There's lots of different possible return codes -- often 255 -- so that they can return different codes for different errors. true returns 0, and false returns 1, so that it can be used properly in the shell.

Code:

true && echo "this will print"
false && echo "but this won't"
true || echo "neither will this"
false || echo "but this will"

You could consider true and false shortcuts to turn the strings true and false into usable return codes, I suppose.

Apologies if it is taking some time for me to understand.

Don't apologize for trying to learn

I suspect you're getting ahead of yourself a bit though -- trying to tackle big problems in a language before you know enough about the tools or the result. It's still possible to do what you want improvising things you need out of the bits you know but, like a potter without a wheel, the results may look very strange.

Yes, I am trying to get the scripts working and then improve them as I get to know more. I need to get some results quick but need some scripts to do what I need.

---------- Post updated at 06:59 PM ---------- Previous update was at 12:11 PM ----------


This worked

Code:

hello=true
val=1
echo "if $hello || [ $val -eq 3 ]; then"
if $hello || [ $val -eq 3 ]; then
  echo "HELLO"
fi

Exactly, you're getting the idea. You don't usually see true/false used that way, but there's nothing to stop you.

It's still not boolean of course... just looks like it.

Your variable can be true, false, cat, rm, sleep, ping, reboot, and any other command you could possibly cram in that variable. Or an entire universe of invalid commands. If any junk gets in your "booleans" by accident, you'll get bizzare "file not found" errors -- or worse, it might run something you shouldn't have.