gawk: Preface

1 
1 Preface
1 *******
1 
1 Several kinds of tasks occur repeatedly when working with text files.
1 You might want to extract certain lines and discard the rest.  Or you
1 may need to make changes wherever certain patterns appear, but leave the
1 rest of the file alone.  Such jobs are often easy with 'awk'.  The 'awk'
1 utility interprets a special-purpose programming language that makes it
1 easy to handle simple data-reformatting jobs.
1 
1    The GNU implementation of 'awk' is called 'gawk'; if you invoke it
1 with the proper options or environment variables, it is fully compatible
1 with the POSIX(1) specification of the 'awk' language and with the Unix
1 version of 'awk' maintained by Brian Kernighan.  This means that all
1 properly written 'awk' programs should work with 'gawk'.  So most of the
1 time, we don't distinguish between 'gawk' and other 'awk'
1 implementations.
1 
1    Using 'awk' you can:
1 
1    * Manage small, personal databases
1 
1    * Generate reports
1 
1    * Validate data
1 
1    * Produce indexes and perform other document-preparation tasks
1 
1    * Experiment with algorithms that you can adapt later to other
1      computer languages
1 
1    In addition, 'gawk' provides facilities that make it easy to:
1 
1    * Extract bits and pieces of data for processing
1 
1    * Sort data
1 
1    * Perform simple network communications
1 
1    * Profile and debug 'awk' programs
1 
1    * Extend the language with functions written in C or C++
1 
1    This Info file teaches you about the 'awk' language and how you can
1 use it effectively.  You should already be familiar with basic system
1 commands, such as 'cat' and 'ls',(2) as well as basic shell facilities,
1 such as input/output (I/O) redirection and pipes.
1 
1    Implementations of the 'awk' language are available for many
1 different computing environments.  This Info file, while describing the
1 'awk' language in general, also describes the particular implementation
1 of 'awk' called 'gawk' (which stands for "GNU 'awk'").  'gawk' runs on a
1 broad range of Unix systems, ranging from Intel-architecture PC-based
1 computers up through large-scale systems.  'gawk' has also been ported
1 to Mac OS X, Microsoft Windows (all versions), and OpenVMS.(3)
1 

Menu

1 
· History                     The history of 'gawk' and
1                                 'awk'.
· Names                       What name to use to find 'awk'.
· This Manual                 Using this Info file. Includes sample
1                                 input files that you can use.
· Conventions                 Typographical Conventions.
· Manual History              Brief history of the GNU project and this
1                                 Info file.
· How To Contribute           Helping to save the world.
· Acknowledgments             Acknowledgments.
1 
1    ---------- Footnotes ----------
1 
1    (1) The 2008 POSIX standard is accessible online at
1 <http://www.opengroup.org/onlinepubs/9699919799/>.
1 
1    (2) These utilities are available on POSIX-compliant systems, as well
1 as on traditional Unix-based systems.  If you are using some other
1 operating system, you still need to be familiar with the ideas of I/O
1 redirection and pipes.
1 
1    (3) Some other, obsolete systems to which 'gawk' was once ported are
1 no longer supported and the code for those systems has been removed.
1