suprisingly you can learn awk from this tiny book. synacticly awk can fit on 2-3 a4 pages anyway. for a good grounding in the approach and feel of these tools get the classic o'reilly tome, but for a goodish intro, refresher or reference this is excellent too
To become proficient in any powerful programming language you really have to emerse yourself in it for some time, and sed and awk are absolutely in that catagory. This little book is therefore a vital aid to short-cutting that process allwoing you to make the most of all the power there is in those utilities. Vital for both beginners and seasoned veterans.