--tool=<tool>::
Use the diff tool specified by <tool>.
Valid merge tools are:
- kdiff3, kompare, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff,
- ecmerge, diffuse, opendiff, p4merge and araxis.
+ araxis, bc3, 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