.. _hg_more:

=============================================================
More commands in hg
=============================================================

.. _hg_revert:

Reverting to a previous version
-------------------------------

This is a continuation of the example in :ref:`myhg`.


#. Now try the following::

        $ rm -f testfile.txt
        $ hg status
        ! testfile.txt

   The first line removes this file (the *-f* flag forces this without
   prompting the user to make sure that's what's intended, since removing files
   can be dangerous).

   The "hg status" command now shows ! next to the file name, indicating
   that a file under version control has disappeared.

   Ordinarily if you remove a file in Unix it's gone.  Period.  But with
   version control, we can easily recover from such a blunder::

        $ hg revert testfile.txt
        $ hg status --all
        C testfile.txt

   The "hg revert" has restored this file using the most recent version
   committed.  You can also use "hg revert" if you make some changes to a
   file and then decide they were a bad idea.  

   Not only can you revert to the most recent version (in the *tip*), you
   can revert to any previous version that was committed.

   Try this::

        $ hg revert -r 0 testfile.txt
        $ hg status
        M testfile.txt

        $ hg diff testfile.txt
        diff -r 11d71622c220 testfile.txt
        --- a/testfile.txt      Tue Mar 02 23:33:52 2010 -0800
        +++ b/testfile.txt      Wed Mar 03 00:01:29 2010 -0800
        @@ -1,3 +1,2 @@ This is a new file
         This is a new file
         with only two lines so far
        -Adding a third line


   Here we have reverted to the version in changeset 0 (the first time we
   committed, when the file only had two lines).  Now "hg status" shows that
   it is modified (relative to the *tip*, which has three
   lines) and "hg diff" shows the change relative to the *tip*: the third
   line was removed.


#. Revert back to the tip::

        $ hg revert --no-backup testfile.txt

   The file should now have 3 lines again.  If the *--no-backup* flag is
   omitted, Mercurial will create a file *testfile.txt.orig* with the
   modified version, just in case you regret your *revert*. (Not all 
   revision control systems have this feature!)

Further reading
---------------