Messages in this thread | | | Date | Thu, 23 Jun 2005 16:56:34 -0700 | From | Matt Mackall <> | Subject | Mercurial vs Updated git HOWTO for kernel hackers |
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On Wed, Jun 22, 2005 at 06:24:54PM -0400, Jeff Garzik wrote: > > Things in git-land are moving at lightning speed, and usability has > improved a lot since my post a month ago: http://lkml.org/lkml/2005/5/26/11
And here's a quick comparison with the current state of Mercurial..
> 1) installing git > > git requires bootstrapping, since you must have git installed in order > to check out git.git (git repo), and linux-2.6.git (kernel repo). I > have put together a bootstrap tarball of today's git repository. > > Download tarball from: > http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-20050622.tar.bz2 > > tarball build-deps: zlib, libcurl, libcrypto (openssl) > > install tarball: unpack && make && sudo make prefix=/usr/local install > > jgarzik helper scripts, not in official git distribution: > http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-new-branch > http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-changes-script > > After reading the rest of this document, come back and update your copy > of git to the latest: > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/git.git
Download from: http://selenic.com/mercurial/mercurial-snapshot.tar.gz Build-deps: Python 2.3 Install: unpack && python setup.py install [--home=/usr/local]
> 2) download a linux kernel tree for the very first time > > $ mkdir -p linux-2.6/.git > $ cd linux-2.6 > $ rsync -a --delete --verbose --stats --progress \ > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git/ > \ <- word-wrapped backslash; sigh > .git/
$ mkdir linux-2.6 $ cd linux-2.6 $ hg init http://www.kernel.org/hg/ # obviously you can also browse this
This downloads about 125M of data, which include the whole kernel history back to 2.4.0 and everything in Linus' git repo as well.
> 3) update local kernel tree to latest 2.6.x upstream ("fast-forward merge") > > $ cd linux-2.6 > $ git-pull-script \ > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
$ hg pull # defaults to where you originally pulled from
It takes about 4M of transfer and well under a minute to pull the entire git history, starting from a base of 2.6.12-rc2.
> 4) check out files from the git repository into the working directory > > $ git checkout -f
$ hg update # or up or checkout or co, depending on your SCM habits
> 5) check in your own modifications (e.g. do some hacking, or apply a patch) > > # go to repo > $ cd linux-2.6 > > # make some modifications > $ patch -sp1 < /tmp/my.patch > $ diffstat -p1 < /tmp/my.patch > > # NOTE: add '--add' and/or '--remove' if files were added or removed > $ git-update-cache <list of all files changed> > > # check in changes > $ git commit
$ hg commit [files] # check in everything changed or just the named files
5.1) undo the last commit or pull
$ hg undo
> 6) List all changes in working dir, in diff format. > > $ git-diff-cache -p HEAD
$ hg status # show changed files
> 7) List all changesets (i.e. show each cset's description text) in local > branch of local tree, that are not present in remote tree. > > $ cd my-kernel-tree-2.6 > $ git-changes-script -L ../linux-2.6 | less
$ hg history | less # How does git know what's not in the # remote tree? Psychic?
> 8) List all changesets: > > $ git-whatchanged
$ hg history | less
> 9) apply all patches in a Berkeley mbox-format file > > First, download and add to your PATH Linus's git tools: > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/git-tools.git > > $ cd my-kernel-tree-2.6 > $ dotest /path/to/mbox # yes, Linus has no taste in naming scripts
hg doesn't do mboxes directly, but you can do:
$ cat patch-list | xargs hg import
> 10) don't forget to download tags from time to time. > > git-pull-script only downloads sha1-indexed object data, and the > requested remote head. This misses updates to the .git/refs/tags/ and > .git/refs/heads directories. It is advisable to update your kernel .git > directories periodically with a full rsync command, to make sure you got > everything: > > $ cd linux-2.6 > $ rsync -a --delete --verbose --stats --progress \ > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git/ > \ <- word-wrapped backslash; sigh > .git/
Tags in mercurial are properly version controlled and come along for the ride with pulls. Also, the right thing happens with merges. > 11) list all branches, such as those found in my netdev-2.6 or > libata-dev trees. > > Download > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/netdev-2.6.git > or > rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git > > > $ cd netdev-2.6 > $ ls .git/refs/heads/ > > { these are the current netdev-2.6 branches } > >8139cp forcedeth master qeth smc91x we18 > >8139too-iomap for-linus natsemi r8169 smc91x-eeprom wifi > >airo hdlc ns83820 register-netdev starfire > >atmel ieee80211 orinoco remove-drivers tlan > >chelsio iff-running orinoco-hch sis900 veth > >dm9000 janitor ppp skge viro
$ hg heads # Has Andrew mentioned your git forest gives him a headache?
> 12) make desired branch current in working directory > > $ git checkout -f $branch
$ hg update -C <rev or id or tag>
> 13) create a new branch, and make it current > > $ cp .git/refs/heads/master .git/refs/heads/my-new-branch-name > $ git checkout -f my-new-branch-name
Since the hg repo is lightweight, this is usually done by just having different directories. Thus we don't explicitly name branches.
$ mkdir new-branch $ cd new-branch $ hg init -u ../linux # makes hardlinks and does a checkout
> 14) examine which branch is current > > $ ls -l .git/HEAD
$ echo $PWD
> 15) undo all local modifications (same as checkout): > > $ git checkout -f
$ hg update -C
> 16) obtain a diff between current branch, and master branch > > In most trees WITH BRANCHES, .git/refs/heads/master contains the current > 'vanilla' upstream tree, for easy diffing and merging. (in trees > without branches, 'master' simply contains your latest changes) > > $ git-diff-tree -p master HEAD
$ hg diff -r <rev> -r <rev>
17) run a browsable, pullable repo server of the current repo on your local machine
$ hg serve
18) push your changes to a remote server
$ hg push ssh://user@host/path/ # aliases and defaults in .hgrc
19) get per-file history
$ hg log <file> | less
20) get annotated file contents
$ hg annotate [file]
21) record that a file has been copied or renamed for the next commit
$ hg copy <source> <dest>
22) get online help
$ hg help [command]
More info at http://selenic.com/mercurial/
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