awk — column processing without writing a script

## Print columns
`awk '{print $1}' file` — first whitespace-separated field
`awk '{print $NF}' file` — last field
`awk -F, '{print $2}' file.csv` — comma-separated
`awk -F'\t' '{print $3}' file.tsv` — tab-separated

## Filter rows
`awk '$3 > 100' file` — rows where col 3 > 100
`awk '/error/' log` — rows matching /error/
`awk 'NR>1' file` — skip header (`NR` is row number)
`awk 'NR==5' file` — only row 5

## Combine filter + print
`awk -F, '$3 > 100 {print $1, $3}' file.csv` — filtered, two columns
`awk -F, 'NR>1 {print $2}' file.csv` — skip header, print col 2

## Aggregations
`awk '{sum+=$1} END {print sum}' file` — sum col 1
`awk '{sum+=$1; n++} END {print sum/n}' file` — mean col 1
`awk '{print NR, $0}' file` — add line numbers

## Field count
`awk '{print NF}' file` — number of fields per line