Someone a while back posted a query about what to read on getting to know the command line. I suggested
Scott Granneman 'Linux Phrasebook'
which is really nice, compact physically and in pages. Since then I've been looking some more on behalf of a colleague who has moved to Linux and is reaching the limits of point and click, and have come on two others which may be useful to someone. The first is:
William Shotts 'The Linux Command Line'
A long very carefully written book, available in pdf for download and from Lulu in paper form. I've only read the first few pages, and then skimmed here and there, but this seems quite exceptionally patiently and carefully written, anyway, its free to download in pdf form before you buy in the paper version, from
http://gd.tuwien.ac.at/linuxcommand.org/tlcl.php
The second one is
Glen Smith 'An introduction to shell scripting'. There are some excerpts available on the site
http://slashetcbooks.co.uk/itss.html
and this also looks very carefully written for pedagogical purposes. Its quite a bit cheaper if you buy direct from them. There is supposed to be an awk book coming as well, but it seems that parenthood has got somewhat in the way of getting that one finished. As it does.
Both of these guys, and Granneman also, seem to understand the difference between teaching and describing, which is a pretty rare talent in any field. I'm sure there are a lot better books for the experienced, or to use as references, but for someone who wants to be taught from first principles they seem pretty good. See how my friend gets on anyway.
Peter