Only a single topic with regards to parameter expansion remains: substring expansion. While you might have heard of a substring, it could also be a very complex-sounding term.
Fortunately, it is actually really really simple. If we take a string, such as Today is a great day, then any part of that sentence that is in the correct order but not the full sentence can be considered a substring of the full string. Examples of this are as follows:
- Today is
- a great day
- day is a gre
- Today is a great da
- o
- (<- there is a space here, you just can't see it)
As you can see from these examples, we're not looking at the semantic meaning of the sentence, but simply at the characters: any number of characters in the correct order can ...
