http://www.scootersoftware.com/support.php?zz=kb_vcs_osx
I tried using the advice from here, but there's no Windows command line I can use.
For SourceTree it says this:
SOURCETREE
From the Beyond Compare menu, Install Command Line Tools. Then:
Visual Diff Tool: Other
Diff Command:/usr/local/bin/bcomp
Parameters:-ro $LOCAL $REMOTE
Merge Tool: Other
Merge Command:/usr/local/bin/bcomp
Parameters:$LOCAL $REMOTE $BASE $MERGED
I also tried to use as the Diff Command "C:\Program Files\Beyond Compare 2\BC2.exe" (with double quotes), but I am not getting Beyond Compare 2 to launch to show the comparison.
