String comparison in awk

Question

I need to compare two strings in alphabetic order, not only equality test. I want to know is there way to do string comparison in awk?

Answer 1

Sure it can:

pax$ echo 'hello goodbye' | gawk '{if ($0 == "hello") {print "HELLO"}}' HELLO 

You can also do inequality (ordered) testing as well:

pax> printf 'aaa\naab\naac\naad\n' | gawk '{if ($1 < "aac"){print}}' aaa aab 

Answer 2

You can do string comparison in awk using standard boolean operators, unlike in C where you would have to use strcmp().

echo "xxx yyy" > test.txt

cat test.txt | awk '$1!=$2 { print($1 $2); }'