gawk—pattern scanning and processing language

gawk [ POSIX or GNU style options ] -f program-file [-- ] file ...

gawk [ POSIX or GNU style options ] [ -- ]program-text file ...

gawk is the GNU Project's implementation of the awk programming language. It conforms to the definition of the language in the POSIX 1003.2 Command Language And Utilities Standard. This version in turn is based on the description in The AWK Programming Language, by Aho, Kernighan, and Weinberger, with the additional features found in the System V Release 4 version of UNIX awk. gawk also provides more recent Bell Labs awk extensions, and some GNU-specific extensions.