You can't go wrong with any programming books Brian Kernighan co-wrote, really. I have _The ANSI C Programming Language_ ("K&R"), _The Practice of Programming_, _The AWK Programming Language_, and _The Unix Programming Environment_, and they're all great. Concise, with a lot of depth that reveals itself on repeat reading.
Ieursalimschy's _Programming in Lua_ ("PiL") was written in a similar style. I recommend it quite highly, too. Great language, great programming book.
Also, the PSD, SMM, and USD books (_4.4BSD Programmer's Supplementary Documents_, etc.) are dry, but also have excellent introductions to several classic Unix tools. They're included as documentation in some BSD installations, and should be easy to find otherwise. The intros to lex and yacc are particularly good.
I'm glad you saw this thread. It's always nice to find out somebody actually paid attention to (and appreciated) some advice you put out on the interwebs.
Ieursalimschy's _Programming in Lua_ ("PiL") was written in a similar style. I recommend it quite highly, too. Great language, great programming book.
Also, the PSD, SMM, and USD books (_4.4BSD Programmer's Supplementary Documents_, etc.) are dry, but also have excellent introductions to several classic Unix tools. They're included as documentation in some BSD installations, and should be easy to find otherwise. The intros to lex and yacc are particularly good.