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Getting Started with `awk'
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The basic function of `awk' is to search files for lines (or other
units of text) that contain certain patterns. When a line matches one
of the patterns, `awk' performs specified actions on that line. `awk'
keeps processing input lines in this way until the end of the input
file is reached.
When you run `awk', you specify an `awk' "program" which tells `awk'
what to do. The program consists of a series of "rules". (It may also
contain "function definitions", but that is an advanced feature, so we
will ignore it for now. User-defined)
Each rule specifies one pattern to search for, and one action to
perform when that pattern is found.
Syntactically, a rule consists of a pattern followed by an action.
The action is enclosed in curly braces to separate it from the pattern.
Rules are usually separated by newlines. Therefore, an `awk' program
looks like this:
PATTERN { ACTION }
PATTERN { ACTION }
...
* Menu:
* Very Simple A very simple example.
* Two Rules A less simple one-line example with two rules.
* More Complex A more complex example.
* Running gawk How to run `gawk' programs;
includes command line syntax.
* Comments Adding documentation to `gawk' programs.
* Statements/Lines Subdividing or combining statements into lines.
* When When to use `gawk' and
when to use other things.