--tool=<tool>::
Use the diff tool specified by <tool>.
Valid diff tools are:
- araxis, bc3, diffuse, emerge, ecmerge, gvimdiff, kdiff3,
- kompare, meld, opendiff, p4merge, tkdiff, vimdiff and xxdiff.
+ araxis, bc3, deltawalker, diffuse, emerge, ecmerge, gvimdiff,
+ kdiff3, kompare, meld, opendiff, p4merge, tkdiff, vimdiff and
+ xxdiff.
+
If a diff tool is not specified, 'git difftool'
will use the configuration variable `diff.tool`. If the