Running `awk' without Input Files
---------------------------------

   You can also run `awk' without any input files.  If you type the
command line:

     awk 'PROGRAM'

then `awk' applies the PROGRAM to the "standard input", which usually
means whatever you type on the terminal.  This continues until you
indicate end-of-file by typing `Control-d'.

   For example, if you execute this command:

     awk '/th/'

whatever you type next is taken as data for that `awk' program.  If you
go on to type the following data:

     Kathy
     Ben
     Tom
     Beth
     Seth
     Karen
     Thomas
     Control-d

then `awk' prints this output:

     Kathy
     Beth
     Seth

as matching the pattern `th'.  Notice that it did not recognize
`Thomas' as matching the pattern.  The `awk' language is "case
sensitive", and matches patterns exactly.  (However, you can override
this with the variable `IGNORECASE'.  *Note Case-sensitivity in
Matching: Case-sensitivity.)