vimwiki

Awk

Text processing tool. Manipulate and analyse text files in a line by line manner. Useful for extracting fields, filtering data, performing calculations.

Basics

awk 'pattern { action }' input_file

• Pattern: optional condition, if met, trigger the action.
• Action: action(s) performed on each lines that match the pattern.
• Input file: if omitted it takes the standard input.

Print command

Print for each lines the given field. By default, fields are separated by spaces. The field to print is specified with $n.

awk '{ print $2, $3 }' input_file

The field separator can be specified with the -F flag.

awk -F ',' '{ print $5 }' input_file

Built in variable

• NR current line number
• NF number of fileds in current line
• $0 entire current line
• $1, $2…individual fields of current line

Condition

awk '{ if ($1 > 10) print $0 }' input_file