There are two ways to run awk. A simple awk command can be run from the command line. More complex tasks should be written as awk programs ("scripts") to a file. Examples of each are provided below.

Example: % awk 'pattern {action}' input-file > output-file

meaning: take each line of the input file; if the line contains the pattern apply the action to the line and write the resulting line to the output-file.

If the pattern is omitted, the action is applied to all lines:

% awk '{action}' input-file > output-file

By default, awk works on files that have columns of numbers or strings that are separated by white space (tabs or spaces), but the -F option can be used if the columns are separated by another character. awk refers to the first column as $1, the second column as $2, etc. The whole line referred to as $0.

Related Resources:

Command Library
Unix commands are introducted one by one, with examples.