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gawk: Foreword3

 
 Foreword to the Third Edition
 *****************************
 
 Arnold Robbins and I are good friends.  We were introduced in 1990 by
 circumstances--and our favorite programming language, AWK. The
 circumstances started a couple of years earlier.  I was working at a new
 job and noticed an unplugged Unix computer sitting in the corner.  No
 one knew how to use it, and neither did I. However, a couple of days
 later, it was running, and I was 'root' and the one-and-only user.  That
 day, I began the transition from statistician to Unix programmer.
 
    On one of many trips to the library or bookstore in search of books
 on Unix, I found the gray AWK book, a.k.a. Alfred V. Aho, Brian W.
 Kernighan, and Peter J. Weinberger's 'The AWK Programming Language'
 (Addison-Wesley, 1988).  'awk''s simple programming paradigm--find a
 pattern in the input and then perform an action--often reduced complex
 or tedious data manipulations to a few lines of code.  I was excited to
 try my hand at programming in AWK.
 
    Alas, the 'awk' on my computer was a limited version of the language
 described in the gray book.  I discovered that my computer had "old
 'awk'" and the book described "new 'awk'."  I learned that this was
 typical; the old version refused to step aside or relinquish its name.
 If a system had a new 'awk', it was invariably called 'nawk', and few
 systems had it.  The best way to get a new 'awk' was to 'ftp' the source
 code for 'gawk' from 'prep.ai.mit.edu'.  'gawk' was a version of new
 'awk' written by David Trueman and Arnold, and available under the GNU
 General Public License.
 
    (Incidentally, it's no longer difficult to find a new 'awk'.  'gawk'
 ships with GNU/Linux, and you can download binaries or source code for
 almost any system; my wife uses 'gawk' on her VMS box.)
 
    My Unix system started out unplugged from the wall; it certainly was
 not plugged into a network.  So, oblivious to the existence of 'gawk'
 and the Unix community in general, and desiring a new 'awk', I wrote my
 own, called 'mawk'.  Before I was finished, I knew about 'gawk', but it
 was too late to stop, so I eventually posted to a 'comp.sources'
 newsgroup.
 
    A few days after my posting, I got a friendly email from Arnold
 introducing himself.  He suggested we share design and algorithms and
 attached a draft of the POSIX standard so that I could update 'mawk' to
 support language extensions added after publication of 'The AWK
 Programming Language'.
 
    Frankly, if our roles had been reversed, I would not have been so
 open and we probably would have never met.  I'm glad we did meet.  He is
 an AWK expert's AWK expert and a genuinely nice person.  Arnold
 contributes significant amounts of his expertise and time to the Free
 Software Foundation.
 
    This book is the 'gawk' reference manual, but at its core it is a
 book about AWK programming that will appeal to a wide audience.  It is a
 definitive reference to the AWK language as defined by the 1987 Bell
 Laboratories release and codified in the 1992 POSIX Utilities standard.
 
    On the other hand, the novice AWK programmer can study a wealth of
 practical programs that emphasize the power of AWK's basic idioms:
 data-driven control flow, pattern matching with regular expressions, and
 associative arrays.  Those looking for something new can try out
 'gawk''s interface to network protocols via special '/inet' files.
 
    The programs in this book make clear that an AWK program is typically
 much smaller and faster to develop than a counterpart written in C.
 Consequently, there is often a payoff to prototyping an algorithm or
 design in AWK to get it running quickly and expose problems early.
 Often, the interpreted performance is adequate and the AWK prototype
 becomes the product.
 
    The new 'pgawk' (profiling 'gawk'), produces program execution
 counts.  I recently experimented with an algorithm that for n lines of
 input, exhibited ~ C n^2 performance, while theory predicted ~ C n log n
 behavior.  A few minutes poring over the 'awkprof.out' profile
 pinpointed the problem to a single line of code.  'pgawk' is a welcome
 addition to my programmer's toolbox.
 
    Arnold has distilled over a decade of experience writing and using
 AWK programs, and developing 'gawk', into this book.  If you use AWK or
 want to learn how, then read this book.
 
      Michael Brennan
      Author of 'mawk'
      March 2001
 
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