GNU diff is the reference for all of these results. Prepare tests: $ echo '[alias]' >> $HGRCPATH $ echo 'ndiff = diff --nodates' >> $HGRCPATH $ hg init $ printf 'hello world\ngoodbye world\n' >foo $ hg ci -Amfoo -ufoo adding foo Test added blank lines: $ printf '\nhello world\n\ngoodbye world\n\n' >foo >>> two diffs showing three added lines <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ + hello world + goodbye world + $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ + hello world + goodbye world + >>> no diffs <<< $ hg ndiff -B $ hg ndiff -Bb Test added horizontal space first on a line(): $ printf '\t hello world\ngoodbye world\n' >foo >>> four diffs showing added space first on the first line <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world + hello world goodbye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world + hello world goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world + hello world goodbye world $ hg ndiff -Bb diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world + hello world goodbye world Test added horizontal space last on a line: $ printf 'hello world\t \ngoodbye world\n' >foo >>> two diffs showing space appended to the first line <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world +hello world goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world +hello world goodbye world >>> no diffs <<< $ hg ndiff -b $ hg ndiff -Bb Test added horizontal space in the middle of a word: $ printf 'hello world\ngood bye world\n' >foo >>> four diffs showing space inserted into "goodbye" <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +good bye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +good bye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +good bye world $ hg ndiff -Bb diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +good bye world Test increased horizontal whitespace amount: $ printf 'hello world\ngoodbye\t\t \tworld\n' >foo >>> two diffs showing changed whitespace amount in the last line <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ hello world -goodbye world +goodbye world >>> no diffs <<< $ hg ndiff -b $ hg ndiff -Bb Test added blank line with horizontal whitespace: $ printf 'hello world\n \t\ngoodbye world\n' >foo >>> three diffs showing added blank line with horizontal space <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world + goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world + goodbye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world + goodbye world >>> no diffs <<< $ hg ndiff -Bb Test added blank line with other whitespace: $ printf 'hello world\n \t\ngoodbye world \n' >foo >>> three diffs showing added blank line with other space <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ -hello world -goodbye world +hello world + +goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ -hello world -goodbye world +hello world + +goodbye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world + goodbye world >>> no diffs <<< $ hg ndiff -Bb Test whitespace changes: $ printf 'helloworld\ngoodbye\tworld \n' >foo >>> four diffs showing changed whitespace <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world -goodbye world +helloworld +goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world -goodbye world +helloworld +goodbye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world +helloworld goodbye world $ hg ndiff -Bb diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,2 @@ -hello world +helloworld goodbye world >>> no diffs <<< $ hg ndiff -w Test whitespace changes and blank lines: $ printf 'helloworld\n\n\n\ngoodbye\tworld \n' >foo >>> five diffs showing changed whitespace <<< $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ -hello world -goodbye world +helloworld + + + +goodbye world $ hg ndiff -B diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ -hello world -goodbye world +helloworld + + + +goodbye world $ hg ndiff -b diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ -hello world +helloworld + + + goodbye world $ hg ndiff -Bb diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ -hello world +helloworld + + + goodbye world $ hg ndiff -w diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,5 @@ hello world + + + goodbye world >>> no diffs <<< $ hg ndiff -wB Test \r (carriage return) as used in "DOS" line endings: $ printf 'hello world\r\n\r\ngoodbye\rworld\n' >foo $ hg ndiff diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ -hello world -goodbye world +hello world\r (esc) +\r (esc) +goodbye\r (no-eol) (esc) world No completely blank lines to ignore: $ hg ndiff --ignore-blank-lines diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ -hello world -goodbye world +hello world\r (esc) +\r (esc) +goodbye\r (no-eol) (esc) world Only new line noticed: $ hg ndiff --ignore-space-change diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world +\r (esc) goodbye world $ hg ndiff --ignore-all-space diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ hello world +\r (esc) goodbye world New line not noticed when space change ignored: $ hg ndiff --ignore-blank-lines --ignore-all-space Do not ignore all newlines, only blank lines $ printf 'hello \nworld\ngoodbye world\n' > foo $ hg ndiff --ignore-blank-lines diff -r 540c40a65b78 foo --- a/foo +++ b/foo @@ -1,2 +1,3 @@ -hello world +hello +world goodbye world Test hunk offsets adjustments with --ignore-blank-lines $ hg revert -aC reverting foo $ printf '\nb\nx\nd\n' > a $ printf 'b\ny\nd\n' > b $ hg add a b $ hg ci -m add $ hg cat -r . a > b $ hg cat -r . b > a $ hg diff -B --nodates a > ../diffa $ cat ../diffa diff -r 0e66aa54f318 a --- a/a +++ b/a @@ -1,4 +1,4 @@ b -x +y d $ hg diff -B --nodates b > ../diffb $ cat ../diffb diff -r 0e66aa54f318 b --- a/b +++ b/b @@ -1,3 +1,3 @@ b -y +x d $ hg revert -aC reverting a reverting b $ hg import --no-commit ../diffa applying ../diffa $ hg revert -aC reverting a $ hg import --no-commit ../diffb applying ../diffb $ hg revert -aC reverting b