GNU Info

(gawk.info)Preface

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Preface
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   Several kinds of tasks occur repeatedly when working with text files.
You might want to extract certain lines and discard the rest.  Or you
may need to make changes wherever certain patterns appear, but leave
the rest of the file alone.  Writing single-use programs for these
tasks in languages such as C, C++ or Pascal is time-consuming and
inconvenient.  Such jobs are often easier with `awk'.  The `awk'
utility interprets a special-purpose programming language that makes it
easy to handle simple data-reformatting jobs.

   The GNU implementation of `awk' is called `gawk'; it is fully
compatible with the System V Release 4 version of `awk'.  `gawk' is
also compatible with the POSIX specification of the `awk' language.
This means that all properly written `awk' programs should work with
`gawk'.  Thus, we usually don't distinguish between `gawk' and other
`awk' implementations.

   Using `awk' allows you to:

   * Manage small, personal databases

   * Generate reports

   * Validate data

   * Produce indexes and perform other document preparation tasks

   * Experiment with algorithms that you can adapt later to other
     computer languages.

   In addition, `gawk' provides facilities that make it easy to:

   * Extract bits and pieces of data for processing

   * Sort data

   * Perform simple network communications.

   This Info file teaches you about the `awk' language and how you can
use it effectively.  You should already be familiar with basic system
commands, such as `cat' and `ls',(1) as well as basic shell facilities,
such as Input/Output (I/O) redirection and pipes.

   Implementations of the `awk' language are available for many
different computing environments.  This Info file, while describing the
`awk' language in general, also describes the particular implementation
of `awk' called `gawk' (which stands for "GNU awk").  `gawk' runs on a
broad range of Unix systems, ranging from 80386 PC-based computers, up
through large-scale systems, such as Crays. `gawk' has also been ported
to Mac OS X, MS-DOS, Microsoft Windows (all versions) and OS/2 PC's,
Atari and Amiga micro-computers, BeOS, Tandem D20, and VMS.

History

The history of `gawk' and

`awk'.

Names

What name to use to find `awk'.

This Manual

Using this Info file. Includes sample

input files that you can use.

Conventions

Typographical Conventions.

Manual History

Brief history of the GNU project and this

Info file.

How To Contribute

Helping to save the world.

Acknowledgments

Acknowledgments.

   ---------- Footnotes ----------

   (1) These commands are available on POSIX-compliant systems, as well
as on traditional Unix based systems. If you are using some other
operating system, you still need to be familiar with the ideas of I/O
redirection and pipes.