PATH, HOME, and ~

One of the reasons I decided to start using this Infinite Ink 
group again is because of a discussion I was participating in in 
comp.mail.pine that veered off on a lot of tangents that are not 
necessarily interesting to Pine users. One of the topics brought 
up by Beartooth is this:

"Incidentally, I'm having troubles getting straight what PATH, 
HOME, and ~ are; and of course that's no part of a pine topic, 
but a prerequisite; otoh, there's nothing, apparently, in man 
pages, info pages, --help, or -h for them."

The traditional place to learn about these is in the man page 
for your shell, for example one of these:

  man bash
  man tcsh

To find out what shell you are using, run one of these:

  finger username
  printenv SHELL

E.g.:

  finger beartooth

I recommend that everyone who spends a lot of time at a 
Unix-like command-line prompt read the man page for your shell!

To get you started learning about PATH, HOME, and ~, type each 
of the following at a command-line prompt:

  printenv PATH
  printenv HOME
  printenv

These 3 commands 'print' something about your shell's 
environment. Details are in the man pages.

To learn about '~', read the 'Tilde Expansion' section of the 
man page for your shell, e.g., type 'man bash' and then do a 
search by typing:

  /Tilde Expansion
  n
  n

where you type 'n' (next) as many times as you need to get to 
the Tilde Expansion section of the man page.

In most of the instructions that I wrote for Beartooth, '~' was 
a synonym for $HOME, but note that this is not always the case.

If anyone has any comments or suggestions for good ways to learn 
about this stuff, please post a followup in this thread.

Thanks,
Nancy