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The AWK syntax

The awk syntax is:
awk '[pattern] {action} [pattern]' input.txt > output.txt
The awk line is always placed between single-quotation (') and not back-quotation (`).
The awk structure is composed of patterns and actions.
1. The [pattern] (optional feature) can be:

  • BEGIN {action} (actions computed before reading the input).
  • END {action} (actions computed at the end of the input).

2. The main action ({action}) is computed by reading the input line by line. The actions include commands and operations.
Therefore the full awk syntax can be represented in this way:
awk 'BEGIN {action} {action} END {action}' input.txt > output.txt
in practice
awk 'BEGIN {action before the input.txt reading } {action during the input.txt reading} END {action after the input.txt reading}' input.txt > output.txt

wiki/awksintax.txt · Last modified: 2021/01/20 20:36 (external edit)