History of AWK

History of AWK

The name awk comes from the initials of its designers: Alfred V. Aho, Peter J. Weinberger, and Brian W. Kernighan. The original version of awk was written in 1977. In 1985 a new versionmade the programming language more powerful, introducing user-de ned functions, multiple inputstreams, and computed regular expressions. This new version became generally available with System V Release 3.1. The version in System V Release 4 added some new features and also cleaned up the behavior in some of the \dark corners" of the language. The speci cation for awk in the posix Command Language and Utilities standard further clari ed the language.

We need to thank many people for their assistance in producing this manual. Jay Fenlason contributed many ideas and sample programs. Richard Mlynarik and Robert J. Chassell gave helpful comments on early drafts of this manual. The paper A Supplemental Document for awk by John W. Pierce of the Chemistry Department at UC San Diego, pinpointed several issues relevant both to awk implementation and to this manual, that would otherwise have escaped us. David Trueman, Pat Rankin, and Michal Jaegermann also contributed sections of the manual.

The following people provided many helpful comments on this edition of the manual: Rick Adams, Michael Brennan, Rich Burridge, Diane Close, Christopher (\Topher") Eliot, Michael Lijewski, Pat Rankin, Miriam Robbins, and Michal Jaegermann. Robert J. Chassell provided much valuable advice on the use of Texinfo.

Little more About AWK :

The term awk refers to a particular program, and to the language you use to tell this program what to do. When we need to be careful, we call the program \the awk utility" and the language \the awk language." The term gawk refers to a version of awk developed as part the GNU project. The purpose of this manual is to explain both the awk language and how to run the awk utility. The term awk program refers to a program written by you in the awk programming language. Most of the time complete awk programs are used as examples, but in some of the more advanced sections, only the part of the awk program that illustrates the concept being described is shown.

Data Files for the Examples :

Many of the examples in this manual take their input from two sample data les. The rst, called `BBS-list', represents a list of computer bulletin board systems together with information about those systems. The second data le, called `inventory-shipped', contains information about shipments on a monthly basis. Each line of these les is one record.

In the le `BBS-list', each record contains the name of a computer bulletin board, its phone number, the board's baud rate, and a code for the number of hours it is operational. An `A' in the last column means the board operates 24 hours a day. A `B' in the last column means the board

operates evening and weekend hours, only. A `C' means the board operates only on weekends.

aardvark 555-5553 1200/300 B

alpo-net 555-3412 2400/1200/300 A

barfly 555-7685 1200/300 A

bites 555-1675 2400/1200/300 A

camelot 555-0542 300 C

core 555-2912 1200/300 C

fooey 555-1234 2400/1200/300 B

foot 555-6699 1200/300 B

macfoo 555-6480 1200/300 A

sdace 555-3430 2400/1200/300 A

sabafoo 555-2127 1200/300 C

The second data le, called `inventory-shipped', represents information about shipments during the year. Each record contains the month of the year, the number of green crates shipped, the number of red boxes shipped, the number of orange bags shipped, and the number of blue packages shipped, respectively. There are 16 entries, covering the 12 months of one year and 4 months of the next year.

Jan 13 25 15 115

Feb 15 32 24 226

Mar 15 24 34 228

Apr 31 52 63 420

May 16 34 29 208

Jun 31 42 75 492

Jul 24 34 67 436

Aug 15 34 47 316

Sep 13 55 37 277

Oct 29 54 68 525

Nov 20 87 82 577

Dec 17 35 61 401

Jan 21 36 64 620

Feb 26 58 80 652

Mar 24 75 70 495

Apr 21 70 74 514