Manpages
Best use hg help (or man hg on unix) of your locally installed Mercurial for up-to-date help information covering the version you have installed (see WhatsNew for version information).
The man pages hg(1) and hgrc(5) are also available in html-format in the release tarballs as doc/hg.1.html and doc/hgrc.5.html.
Links to online-versions of the manpages:
man page
URL
hg(1)
hgmerge(1)
hgignore(5)
hgrc(5)
Notes:
As of Mercurial 1.0, hgmerge is no longer installed by default; but if it's installed, hg will use it (see MergeToolConfiguration)
See also: TranslatedManPages, FAQ, TipsAndTricks, UnderstandingMercurial