Print Lines having unique fields

Tuesday, April 23, 2013 awk 0 Comments

I have a table in which most of the values in a given row are the same. What I want to pull out are any rows where at least one of the values is different.
For example I have a file:

one one one one two
two two two two two
three four four five

I found a nice trick for doing this:

awk '{f=$0;gsub($1,"")}NF{print f}' file
one one one one two
three four four five

First we store the line in original state f=$0 then we do a global substitution on everything matching the first field, if all fields are the same then nothing will be left therefor NF will be 0 and nothing will be printed else we print the original line.