Tune a bit the extdiff toplevel comments/samples. * Capitalize the first letter of all sentences * Add an example for GNU diff(1) 'context diff' mode. * Explain the requirement for separate cmd.xxx and opts.xxx options in .hgrc, which hopefully will guard against users trying to add: [extdiff] # Add a new Mercurial command called `cdiff', which calls # GNU diff(1) in 'context diff' mode. cmd.cdiff = diff -Nprc5 which fails for recent crew builds with: $ hg cdiff . making snapshot of 1 files from rev 07dc4a569f4e making snapshot of 1 files from working dir diff -Nprc5: not found The correct way to do this is by separating the cmd.cdiff and opts.cdiff parts like this: [extdiff] # Add a new Mercurial command called `cdiff', which calls # GNU diff(1) in 'context diff' mode. cmd.cdiff = diff opts.cdiff = -Nprc5 so add it as a new example and explicitly describe it in the extdiff comments.