Hi Jenny,

So indeed, the problem is simply that you don't have
write permissions to ~/data/pl. Use the command:

chmod u+w ~/data/pl

to fix that.

----

I haven't looked at the recent books on shells, but I
do know that there are many available. The one
thing to note is that many are geared to /bin/bash,
but that many not be the shell you want to use (we
do most of our work with /bin/tcsh, the T-shell).

A quick google search turned up a one page doc:
[freeengineer.org]
That "learn UNIX in 10 minutes" is a nice overview,
and mentions both tcsh and bash.

HowTo #1 covers the basic details of shell scripting,
and HowTo #2 and #0 may also be worth reading.

- rick