Making a progress gauge in a bash script

Hello once again:
One thing that seems to be a nice feature is a progress gauge... so I can see how long an operation will take for a task to complete if it is requiring a lot of processing or the file is enormous. I have seen references to gauge operations, but I don't know anything about it or how to use it, or anything like that. Can some give me an example of creating a gauge, text based, not graphical, or direct me to a decent tutorial? Thank you!

This site was mentioned in an earlier post and it looks pretty good:
Theiling Online: ASCII bar