Awk from introduction to earth (0) overview of awk

1、 Introduce

AWK Is a text processing language , The language is 1977 Born in Bell Labs , Has experienced 40 Years of development . It supports POSIX standard , There are several standard compliant implementations , stay 2020 In, there are still a large number of fans , Whether for simple text processing tasks or for processing “ big data ”.

Its name comes from its author's initials ：Alfred Aho,Peter Weinberger and Brian Kernighan.AWK It's the core Unix Tools , It aims to do one thing ： Filter and convert text lines . It is usually used to parse fields in log files , Convert the output of other tools and calculate the number of occurrences of words and fields .

from GNU/Linux released AWK Versions are often called GNU AWK, By the free software Fund （ Free Software Foundation, FSF） Responsible for development and maintenance .

Various AWK edition

Currently in use AWK There are three major versions , And they all conform to POSIX standard （ At least for most use cases , Close enough to ）. The first is classic awk, It is Aho,Weinberger and Kernighan In their 《 AWK programing language 》 It's described in a book AWK edition . Sometimes called “ new AWK”（nawk） or “ A real AWK”, Now the trust is in GitHub On . This is based on many BSD The system of （ Include macOS） Pre installed version on （ Even though macOS The attached version is out of date , Need to upgrade ）.

The second is GNU Awk（gawk）, It is by far the most powerful , Maintain the most active version .Gawk Usually pre installed in Linux On the system , And usually silent