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