Learning Linux Shell Scripting - Second Edition

Fields

Every line is called a record, and every word in a record is called a field. By default, words or fields are separated by whitespace, that is, Space or Tab. awk has an internal built-in variable called NF, which will keep track of field numbers. Typically, the maximum field number will be 100 and will depend on implementation. The following example has five records and four fields.

    $1    $2        $3       $4
    Bill Thomas  8000  08/9/1968
    Fred Martin  6500  22/7/1982
    Julie Moore  4500  25/2/1978
    Marie Jones  6000  05/8/1972
    Tom Walker   7000  14/1/1977
    $ awk '{print NR, $1, $2, $4}' people.txt
  

The output will be:

    1 Bill Thomas 08/9/1968
    2 Fred Martin 22/7/1982
    3 Julie Moore 25/2/1978
    4 Marie Jones 05/8/1972
    5 Tom Walker  14/1/1977
  

This has printed the record ...