How do I customize the 'commit message file' generated by `hg commit`?

Question

When I run hg commit, Mercurial generates a file for my commit message that looks like this :

HG: Enter commit message.  Lines beginning with \'         


        

Answer 1

It's possible to specify this in the 'committemplate' config section (see 'hg help config.committemplate'):

 "committemplate"
----------------

"changeset"
    String: configuration in this section is used as the template to
    customize the text shown in the editor when committing.

In addition to pre-defined template keywords, commit log specific one
below can be used for customization:

"extramsg"
    String: Extra message (typically 'Leave message empty to abort
    commit.'). This may be changed by some commands or extensions.

For example, the template configuration below shows as same text as one
shown by default:

  [committemplate]
  changeset = {desc}\n\n
      HG: Enter commit message.  Lines beginning with 'HG:' are removed.
      HG: {extramsg}
      HG: --
      HG: user: {author}\n{ifeq(p2rev, "-1", "",
     "HG: branch merge\n")
     }HG: branch '{branch}'\n{if(activebookmark,
     "HG: bookmark '{activebookmark}'\n")   }{subrepos %
     "HG: subrepo {subrepo}\n"              }{file_adds %
     "HG: added {file}\n"                   }{file_mods %
     "HG: changed {file}\n"                 }{file_dels %
     "HG: removed {file}\n"                 }{if(files, "",
     "HG: no files changed\n")}

"diff()"
    String: show the diff (see 'hg help templates' for detail)