A simple and performant command-line diff tool that opens the result in the browser.

Run using differ.exe file1.txt file2.txt [options] with the files you want to diff and eventually options.

Available options:

• unifiedview/splitview: how to display the result (single panel/double panel side-by-side).

• collapselines/expandelines: show all lines in the file or only those with differences and their context.

• contextsize <int>: how many lines of context to display for the collapselines option. 3 by default.

• ignorewhitespace: ignore whitespace differences. Off by default.

• ignorecase: ignore case differences. Off by default.

• lcs/patience: the method to use to compare. "patience" by default.

You can configure external tools to use differ. For example, in SourceTree under Tools > Options > Diff, you can set
External Diff Tool: Custom
Diff Command = "path/to/Differ.exe"
Arguments=""$LOCAL" "$REMOTE" splitview patience collapselines"

You can modify the look of the output by modifying template_split.html or template_unified.html

• improve diff LCS and empty lines
• fix html scrolling background missing
• provide option to tradeoff between number of edits vs total lengh of edits

• last line of diff doesn't show grey background (remove additional new lines) - (happens only left-side?)
• related to above, some mismatch in line numbers in diff
• (ignore spaces in hash computation to avoid opening brackets to match up incorrectly) - parameter
• even if the hashes match up, store both L/R copies in the structure since spaces might be different but ignored
• support non-ascii strings (and sanitize the input with non-printable characters I use)