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Category:AWK: Difference between revisions
Major rewrite. Removes the sentences copied from Wikipedia, but retains a link to Wikipedia's article, and still mentions strings, associative arrays, and the reference implementation.
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(Major rewrite. Removes the sentences copied from Wikipedia, but retains a link to Wikipedia's article, and still mentions strings, associative arrays, and the reference implementation.) |
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{{language
|exec=interpreted
|tag=awk
}}
AWK is a small but powerful programming language that can process and convert text files. AWK is part of every [[Unix]]-derived system, where AWK and [[UNIX Shell]] are the only Unix scripting languages that support both numbers and strings.
Each AWK program consists of pattern-action statements. The program reads each input line, checks lines against patterns, and runs matching actions. For programs that never read input lines, the entire program can be one <code>BEGIN { ... }</code> block.
* ''List users who have /bin/ksh as a shell.''<lang awk>$ awk -F: '$7 == "/bin/ksh" { print $1 }' /etc/passwd</lang>
AWK has only three types of variables: they are strings, floating-point numbers, and associative arrays (where every array index is a string). Conversion between strings and numbers is automatic. AWK also has regular expressions, which appear in many AWK programs. There are a few built-in functions, like cos() and sprintf().
* ''Find average line length.''<lang awk>$ awk '{ cnt += length($0) } END { print cnt / NR }' /etc/rc</lang>
The name "AWK" comes from the initials of Alfred Aho, Peter Weinberger and Brian Kernighan: they invented AWK during the 1970s. A few decades later, Kernighan continues to maintain the [[nawk|reference implementation]] of AWK.
==Links==
*[http://leaf.dragonflybsd.org/cgi/web-man?command=awk§ion=1 awk(1) manual page], short and brief
*[[wp:AWK (programming language)|AWK in Wikipedia]]
*[http://awk.info AWK Community Portal]
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