Example Bourne shell scripts

I've written a bunch of short Bourne shell scripts to illustrate how they work.

• showstuff, which simply combines a few commands into a script
• whon, which automates a pipe
• swap, which illustrates access to command-line arguments
• thrice, more about command-line arguments
• greet, an example of the case statement
• indir, which moves to a specified directory, then executes a specified command
• p3, an answer to an exam question from a previous year; illustrates conditionals
• p3_alternate: another way of handling optional command-line arguments
• p4, an answer to another exam question
• p4_alternate: an even slicker way of writing a self-reproducing shell script
• xprod: an example of back-quoting and for-loops