More shell scripts than one in one text file? Code Answer

I am learning shell scripting for my introductory UNIX course at my university, and I`m curious if is it possible to have more than one shell script in one text file. What I mean by that is, for example in pascal when you have:

var…

begin
end.
//another program which will be ignore

compiler ignores anything after the end with period. Can something like this be done with Shell? I`m asking because I have to go through lot of Shell examples and having many files opened is not very handy, with this I could run the same script without worrying about u+x permissions and just run the script with same name anytime I go to the next code example. So it is possible to have something that will say: end, do not read any further. ? Thank you in anvance for answering this silly question.

Answer

For said purpose – that is stopping the script at any given line – you could simply use exit to break at this point. For any real life application this would seem a little crude though but for learning purposes it should fit.

Say:

#!/bin/sh

# now I am working here
do_something
exit

# this is old, do not execute
did_something
exit

# this is even older, do not execute
did_something_long_ago