tagname.

 * "git describe" warns when using a tag whose name and path contradict
   with each other.

 * "git diff" learned "--relative" option to limit and output paths
   relative to the current directory when working in a subdirectory.

 * "git diff" learned "--dirstat" option to show birds-eye-summary of
   changes more concisely than "--diffstat".

 * "git format-patch" learned --cover-letter option to generate a cover
   letter template.

 * "git gc" learned --quiet option.

 * "git gc" now automatically prunes unreachable objects that are two
   weeks old or older.

 * "git gc --auto" can be disabled more easily by just setting gc.auto
   to zero.  It also tolerates more packfiles by default.

 * "git grep" now knows "--name-only" is a synonym for the "-l" option.

 * "git help <alias>" now reports "'git <alias>' is alias to <what>",
   instead of saying "No manual entry for git-<alias>".

 * "git help" can use different backends to show manual pages and this can
   be configured using "man.viewer" configuration.

 * "gitk" does not restore window position from $HOME/.gitk anymore (it
   still restores the size).

 * "git log --grep=<what>" learned "--fixed-strings" option to look for
   <what> without treating it as a regular expression.

 * "git gui" learned an auto-spell checking.

 * "git push <somewhere> HEAD" and "git push <somewhere> +HEAD" works as
   expected; they push the current branch (and only the current branch).
   In addition, HEAD can be written as the value of "remote.<there>.push"
   configuration variable.

 * When the configuration variable "pack.threads" is set to 0, "git
   repack" auto detects the number of CPUs and uses that many threads.

 * "git send-email" learned to prompt for passwords
   interactively.

 * "git send-email" learned an easier way to suppress CC
   recipients.

 * "git stash" learned "pop" command, that applies the latest stash and
   removes it from the stash, and "drop" command to discard the named
   stash entry.

 * "git submodule" learned a new subcommand "summary" to show the
   symmetric difference between the HEAD version and the work tree version
   of the submodule commits.

 * Various "git cvsimport", "git cvsexportcommit", "git cvsserver",
   "git svn" and "git p4" improvements.

(internal)

 * Duplicated code between git-help and git-instaweb that
   launches user's preferred browser has been refactored.

 * It is now easier to write test scripts that records known
   breakages.

 * "git checkout" is rewritten in C.

 * "git remote" is rewritten in C.

 * Two conflict hunks that are separated by a very short span of common
   lines are now coalesced into one larger hunk, to make the result easier
   to read.

 * Run-command API's use of file descriptors is documented clearer and
   is more consistent now.

 * diff output can be sent to FILE * that is different from stdout.  This
   will help reimplementing more things in C.

Fixes since v1.5.4
------------------

All of the fixes in v1.5.4 maintenance series are included in
this release, unless otherwise noted.

 * "git-http-push" did not allow deletion of remote ref with the usual
   "push <remote> :<branch>" syntax.

 * "git-rebase --abort" did not go back to the right location if
   "git-reset" was run during the "git-rebase" session.

 * "git imap-send" without setting imap.host did not error out but
   segfaulted.