Two-file join on key awk

Left-join data.txt with lookup.txt on first field

awk 'NR==FNR{a[$1]=$2; next} $1 in a {print $0, a[$1]}' lookup.txt data.txt

#awk #linux

more awk all 15 commands →

Print specific column awk '{print $3}' file.txt Custom field separator awk -F: '{print $1, $3}' /etc/passwd Filter rows by pattern awk '/ERROR/ {print NR": "$0}' app.log Sum a column awk '{sum += $4} END {print sum}' access.log Print lines between two patterns awk '/START/,/END/' file.txt