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====== AWK - AWK Fields ======

Assuming a file exists with the following contents:

<file>
10   Peter     Terence   Roux        45
11   Virginia  Genevieve  Roux        45
12   Felix     Devon     Roux         5
13   David     Bruce     Stevenson   48
14   Bob       James     Smith       16
48   Adam      Winter    Ridley      23
</file>

----

===== Understanding Fields =====

<code awk>
awk '{print $1,$2,$3,$4,$5}' test.txt
</code>

returns:

<code>
10 Peter Terence Roux 45
11 Virginia Genevieve Roux 45
12 Felix Devon Roux 5
13 David Bruce Stevenson 48
14 Bob James Smith 16
48 Adam Winter Ridley 23
</code>

<WRAP info>
**NOTE:**  AWK has read each field in the file into the variables $1, $2, $3, etc.

  * Each field is split by a field separator, which by default is a space or comma.
    * As can be seen, it does not matter how many spaces separate each field in the input file.

  * As AWK reads the input, the entire record is assigned to the variable $0.

</WRAP>

----

===== Display Only Certain Fields =====

To only print the name and surname, i.e. fields $2 and $4:

<code awk>
awk '{print $2,$4}' test.txt
</code>

returns:

<code>
Peter Roux
Virginia Roux
Felix Roux
David Stevenson
Bob Smith
Adam Ridley
</code>

The ability to address each field with a unique number allows only specific fields to be output.

<WRAP info>
**NOTE** : Fields can be printed out in any order.  For example:

<code awk>
awk '{print $4,$2}' test.txt
</code>

returns:

<code>
Roux Peter
Roux Virginia
Roux Felix
Stevenson David
Smith Bob
Ridley Adam
</code>

Notice that the surname is now printed before first name.
</WRAP>

----

===== Display Multi-line Output =====

To output onto multiple lines:

<code awk>
awk '{print $2,$3,$4; print $1, $5}' test.txt
</code>

returns:

<code>
Peter Terence Roux
10 45
Virginia Genevieve Roux
11 45
Felix Devon Roux
12 5
David Bruce Stevenson
13 48
Bob James Smith
14 16
Adam Winter Ridley
48 23
</code>

<WRAP info>
**NOTE:**  The semicolon (;) indicates to write some data to a different line.
</WRAP>


This could also be written as the following, which will produce the same results:

<code awk>
awk '{print $2,$3,$4} {print $1, $5}' test.txt
</code>

<WRAP important>
**WARNING:**  Although both uses of code produce the same result here, be warned that they can produce different results when used with more advanced AWK options.
</WRAP>


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