Series: Hayden Books UNIX System Library
Paperback: 512 pages
Publisher: Sams; 1st edition (December 1, 1989)
Product Dimensions: 9.1 x 7.4 x 0.8 inches
Shipping Weight: 1.9 pounds
Average Customer Review: 4.4 out of 5 stars See all reviews (28 customer reviews)
Best Sellers Rank: #1,871,284 in Books (See Top 100 in Books) #54 in Books > Computers & Technology > Operating Systems > Unix > Shell #63 in Books > Computers & Technology > Programming > APIs & Operating Environments > Unix #1844 in Books > Textbooks > Computer Science > Operating Systems
Although published in 1990, this book could still function well as an introduction to UNIX and (Bourne) shell programming, provided one is aware of some changes to the shell in most implementations of UNIX since that date. Also, the Perl language has come on strong in recent years, and depending on your tastes (and time), that language can be used with great efficiency to do the tasks that are traditionally done in the shell. After a quick review of the basics of UNIX, the authors give a purely descriptive explanation of the UNIX shell in chapter 3. Emphasizing that it is an interpretive language, the most commonly used shell commands are discussed in chapter 4, starting with a discussion of regular expressions. The cut, paste, sed, tr, grep, uniq, and sort commands are treated in detail. In chapter 5, one begins the actual task of creating shell programs using shell variables. There is no data typing in the shell, so values can be assigned to variables without noting their type as integer, float, etc. The authors only briefly discuss the mechanism in shell programming. The method by which the shell interprets quotation characters is covered in the next chapter. The single, double, backslash, and back quote characters are discussed in detail. Noting that arithmetic operations are done on values stored in variables in the shell, the authors show to proceed with these operations using the expr program. The mechanisms for passing arguments to shell programs is treated in chapter 7, the authors showing how to write shell programs that take arguments typed on the command line. The role of positional variables for delaying assignment after normal command line processing is discussed.