awk

awk [options] 'pattern {action}' file

awk '{print $1}' file.txt

awk -F: '{print $1, $3}' /etc/passwd

awk '$3 > 1000 {print $1, $3}' /etc/passwd

awk '{sum += $1} END {print sum}' numbers.txt

df -h | awk 'NR>1 && $5+0 > 80 {print $6, $5}'

awk -F, '{print NR": "$2}' data.csv