diff -b -w -E output1 output2
이 경우는 '.'을 무시하고 비교함
diff -b -w -E <(grep -vE '^\s*(.)' output1) <(grep -vE '^\s*(.)' output2)
https://unix.stackexchange.com/questions/17040/how-to-diff-files-ignoring-comments-lines-starting-with