Awk: Difference between revisions

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Example:<br />
Example:<br />
<code> \t </code> means a tab character
<code> \t </code> means a tab character


<code> $ </code> field (column) reference<br />
<code> $ </code> field (column) reference<br />
Example:<br />
Example:<br />
<code>$2</code> tells awk to do something to the 2nd field (column) of the input. (Note that awk does not interpret variables inside strings.)
<code>$2</code> tells awk to do something to the 2nd field (column) of the input. (Note that awk does not interpret variables inside strings.)


<code> ' </code> (single-quote) Specify awk commands inside single quotes at the command line.<br />
<code> ' </code> (single-quote) Specify awk commands inside single quotes at the command line.<br />
Example:<br />
Example:<br />
<code>awk '{print}' file.txt</code> prints the contents of file.txt to the screen
<code>awk '{print}' file.txt</code> prints the contents of file.txt to the screen


<code></code>
<code></code>

Revision as of 16:55, 30 December 2016

awk parses reports, among other text manipulation

Usage:

awk pattern {action}

Example:

example here, if I can figure it out...


Structure

BEGIN

BEGIN The begin block runs at the start of the awk program, and runs only once. The body block is optional.

BODY

/pattern/ {awk-commands} The body block runs on every line of text (this can be restricted with patterns.) There is no keyword for this block.

END

END {awk-commands} The END command runs once at the end of the program.


Operators

\ The \ tells awk that a special character follows the slash, and to interpret it differently than regular text
Example:
\t means a tab character


$ field (column) reference
Example:
$2 tells awk to do something to the 2nd field (column) of the input. (Note that awk does not interpret variables inside strings.)


' (single-quote) Specify awk commands inside single quotes at the command line.
Example:
awk '{print}' file.txt prints the contents of file.txt to the screen


References

  1. awk man page
  2. awk tutorial