You could also do it in one line: cat file1 file2 | awk '!_[tolower($0)]++{ gsub(/^[ \t]+|[ \t]+$/, ""); print}' Does that mean awk doesn't have to worry e

You could also do it in one line: cat file1 file2 | awk '!_[tolower($0)]++{ gsub(/^[ \t]+|[ \t]+$/, ""); print}' Does that mean awk doesn't have to worry either?