Purpose: to describe awk, an early Unix tiny language .
See http://cm.bell-labs.com/cm/cs/awkbook/index.html which is a page for an official book by the creators of the language. See also news:comp.lang.awk . Another good resource for awk documentation is http://www.gnu.org/manual/gawk-3.1.0/gawk.html .
Programmers often come to the Tcl newsgroups asking how can I do this awk like operation in Tcl or how to invoke awk from exec. This is because Awk's ability to scan through a file and manipulate the contents pre-dates Perl's functionality to do this, and frankly awk's abilities, while cruder in many ways, are also simpler (simpler even than Tcl!).