using awk to count the number of occurrences of patterns from another file

awk '
  NR==FNR{a[$0]; next}
    for(i=1; i<=NF; i++){
      if ($i in a){ a[$i]++ }
    for(key in a){ printf "%s %d\n", key, a[key] }
' list.txt target.txt
  • NR==FNR{a[$0]; next} The condition NR==FNR is only true for the first file, so the keys of array a are lines of list.txt.

  • for(i=1; i<=NF; i++) Now for the second file, this loops over all its fields.

    • if ($i in a){ a[$i]++ } This checks if the field $i is present as a key in the array a. If yes, the value (initially zero) associated with that key is incremented.
  • At the END, we just print the key followed by the number of occurrences a[key] and a newline (\n).


blonde 2
red 0
black 0


  1. Because of %d, the printf statement forces the conversion of a[key] to an integer in case it is still unset. The whole statement could be replaced by a simpler print key, a[key]+0. I missed that when writing the answer, but now you know two ways of doing the same thing. 😉

  2. In your attempt you were, for some reason, only addressing field 2 ($2), ignoring other columns.

CLICK HERE to find out more related problems solutions.

Leave a Comment

Your email address will not be published.

Scroll to Top