hg update - update working directory (or switch revisions)

       up, checkout, co

                                                                                                      HG(UPDATE)

       Update  the  repository's  working  directory  to  the specified changeset. If no changeset is specified,
       update to the tip of the current named branch and move the active bookmark (see hghelpbookmarks).

       Update sets the working directory's parent revision to the specified changeset (see hghelpparents).

       If the changeset is not a descendant or  ancestor  of  the  working  directory's  parent  and  there  are
       uncommitted  changes, the update is aborted. With the -c/--check option, the working directory is checked
       for uncommitted changes; if none are found, the working directory is updated to the specified changeset.

       The -C/--clean, -c/--check, and -m/--merge options control what happens if the working directory contains
       uncommitted changes.  At most of one of them can be specified.

       1. If no option is specified, and if the requested changeset is an ancestor or descendant of the  working
          directory's  parent,  the  uncommitted  changes are merged into the requested changeset and the merged
          result is left uncommitted. If the requested changeset is not an ancestor or descendant (that  is,  it
          is on another branch), the update is aborted and the uncommitted changes are preserved.

       2. With  the  -m/--merge option, the update is allowed even if the requested changeset is not an ancestor
          or descendant of the working directory's parent.

       3. With the -c/--check option, the update is aborted and the uncommitted changes are preserved.

       4. With the -C/--clean option, uncommitted changes are discarded and the working directory is updated  to
          the requested changeset.

          To cancel an uncommitted merge (and lose your changes), use hgmerge--abort.

          Use null as the changeset to remove the working directory (like hgclone-U).

          If you want to revert just one file to an older revision, use hgrevert[-rREV]NAME.

          See hghelpdates for a list of formats valid for -d/--date.

          Returns 0 on success, 1 if there are unresolved files.

       hg update - update working directory (or switch revisions)

-C,--clean
              discard uncommitted changes (no backup)

       -c,--check
              require clean working directory

       -m,--merge
              merge uncommitted changes

       -d,--date<DATE>
              tipmost revision matching date

       -r,--rev<REV>
              revision

       -t,--tool<TOOL>
              specify merge tool

       hg update [-C|-c|-m] [-d DATE] [[-r] REV]