File: gawk.info,  Node: Read Terminal,  Next: Long,  Prev: One-shot,  Up: Running gawk

1.1.2 Running 'awk' Without Input Files
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You can also run 'awk' without any input files.  If you type the
following command line:

     awk 'PROGRAM'

'awk' applies the PROGRAM to the "standard input", which usually means
whatever you type on the keyboard.  This continues until you indicate
end-of-file by typing 'Ctrl-d'.  (On non-POSIX operating systems, the
end-of-file character may be different.)

   As an example, the following program prints a friendly piece of
advice (from Douglas Adams's 'The Hitchhiker's Guide to the Galaxy'), to
keep you from worrying about the complexities of computer programming:

     $ awk 'BEGIN { print "Don\47t Panic!" }'
     -| Don't Panic!

   'awk' executes statements associated with 'BEGIN' before reading any
input.  If there are no other statements in your program, as is the case
here, 'awk' just stops, instead of trying to read input it doesn't know
how to process.  The '\47' is a magic way (explained later) of getting a
single quote into the program, without having to engage in ugly shell
quoting tricks.

     NOTE: If you use Bash as your shell, you should execute the command
     'set +H' before running this program interactively, to disable the
     C shell-style command history, which treats '!' as a special
     character.  We recommend putting this command into your personal
     startup file.

   This next simple 'awk' program emulates the 'cat' utility; it copies
whatever you type on the keyboard to its standard output (why this works
is explained shortly):

     $ awk '{ print }'
     Now is the time for all good men
     -| Now is the time for all good men
     to come to the aid of their country.
     -| to come to the aid of their country.
     Four score and seven years ago, ...
     -| Four score and seven years ago, ...
     What, me worry?
     -| What, me worry?
     Ctrl-d