(gawk.info)Reading Files

Reading Input Files
*******************

   In the typical `awk' program, all input is read either from the
standard input (by default the keyboard, but often a pipe from another
command) or from files whose names you specify on the `awk' command
line.  If you specify input files, `awk' reads them in order, reading
all the data from one before going on to the next.  The name of the
current input file can be found in the built-in variable `FILENAME'
(Note: Built-in Variables.).

   The input is read in units called "records", and processed by the
rules of your program one record at a time.  By default, each record is
one line.  Each record is automatically split into chunks called
"fields".  This makes it more convenient for programs to work on the
parts of a record.

   On rare occasions you will need to use the `getline' command.  The
`getline' command is valuable, both because it can do explicit input
from any number of files, and because the files used with it do not
have to be named on the `awk' command line (Note: Explicit Input with
`getline'.).



* Records
Controlling how data is split into records.
* Fields
An introduction to fields.
* Non-Constant Fields
Non-constant Field Numbers.
* Changing Fields
Changing the Contents of a Field.
* Field Separators
The field separator and how to change it.
* Constant Size
Reading constant width data.
* Multiple Line
Reading multi-line records.
* Getline
Reading files under explicit program control
using the `getline' function.