Listmania!
Open Sources
Perl Best PracticesPerl Best Practices by Damian Conway
Buy new: £16.57 / Used from: £15.73
How to write maintainable and sensible Perl
Programming Perl: There's More Than One Way To Do ItProgramming Perl: There's More Than One Way To Do It by Larry Wall
Buy new: £21.51 / Used from: £12.00
The Perl Reference Book. Assumes you know how to program Perl already
Pro OpenSSH (Expert's Voice in Open Source)Pro OpenSSH (Expert's Voice in Open Source) by Michael Stahnke
Buy new: £29.92 / Used from: £6.16
A very practical guide to setting up and using OpenSSH. Assumes you know SSH basics
Running Linux (Essential Guide to Linux)Running Linux (Essential Guide to Linux) by Matt Welsh
Buy used from: £0.68
Excellent Linux overview book (This edition is apparently better than the following one)
Classic Shell Scripting: Hidden Commands that Unlock the Power of UnixClassic Shell Scripting: Hidden Commands that Unlock the Power of Unix by Arnold Robbins
Buy new: £15.12 / Used from: £10.00
How to write good portable POSIX shell. Covers bash, zsh and ksh on Linux and Unix
Object Oriented PerlObject Oriented Perl by Damian Conway
Buy used from: £17.36
Excellent (slightly dated) introduction to object oriented Perl
Effective Perl Programming: 60 Methods and Rules for Scripting Better Programs (A-W Developers Press)Effective Perl Programming: 60 Methods and Rules for Scripting Better Programs (A-W Developers Press) by Joseph N. Hall
Buy new: £22.94 / Used from: £4.66
How to write clean, effective and idiomatic perl. Similar to PBP book
The Debian System: Concepts and TechniquesThe Debian System: Concepts and Techniques by Martin Krafft
Buy new: £36.02 / Used from: £19.99
The perfect book for a Debian 3.1 "Sarge" (or derviative) system administrator