Date: Mon, 15 Aug 2005 12:17:41 -0700
From: tony.luck@intel.com
Subject: Some tutorial text (was git/cogito workshop/bof at linuxconf au?)
+Abstract: In this article, Tony Luck discusses how he uses GIT
+ as a Linux subsystem maintainer.
Here's something that I've been putting together on how I'm using
GIT as a Linux subsystem maintainer.
-I suspect that I'm a bit slap-happy with the "git checkout" commands in
-the examples below, and perhaps missing some of the _true-git_ ways of
-doing things.
-
-Tony
+Last updated w.r.t. GIT 0.99.5
+
Linux subsystem maintenance using GIT
-------------------------------------
$ cd work
-Make a GIT branch named "linus", and rename the "origin" branch as linus too:
+Set up a remotes file so that you can fetch the latest from Linus' master
+branch into a local branch named "linus":
+
+ $ cat > .git/remotes/linus
+ URL: rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
+ Pull: master:linus
+ ^D
- $ git checkout -b linus
- $ mv .git/branches/origin .git/branches/linus
+and create the linus branch:
+
+ $ git branch linus
The "linus" branch will be used to track the upstream kernel. To update it,
you simply run:
- $ git checkout linus && git pull linus
+ $ git fetch linus
+
+you can do this frequently (and it should be safe to do so with pending
+work in your tree, but perhaps not if you are in mid-merge).
+
+If you need to keep track of other public trees, you can add remote branches
+for them too:
-you can do this frequently (as long as you don't have any uncommited work
-in your tree).
+ $ git branch another
+ $ cat > .git/remotes/another
+ URL: ... insert URL here ...
+ Pull: name-of-branch-in-this-remote-tree:another
+ ^D
-If you need to keep track of other public trees, you can add branches for
-them too:
+and run:
- $ git checkout -b another linus
- $ echo URL-for-another-public-tree > .git/branches/another
+ $ git fetch another
Now create the branches in which you are going to work, these start
out at the current tip of the linus branch.
- $ git checkout -b test linus
- $ git checkout -b release linus
+ $ git branch test linus
+ $ git branch release linus
These can be easily kept up to date by merging from the "linus" branch:
$ git checkout test && git resolve test linus "Auto-update from upstream"
$ git checkout release && git resolve release linus "Auto-update from upstream"
-Set up so that you can push upstream to your public tree:
+Set up so that you can push upstream to your public tree (you need to
+log-in to the remote system and create an empty tree there before the
+first push).
- $ echo master.kernel.org:/ftp/pub/scm/linux/kernel/git/aegl/linux-2.6.git > .git/branches/origin
+ $ cat > .git/remotes/mytree
+ URL: master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6.git
+ Push: release
+ Push: test
+ ^D
-and then push each of the test and release branches using:
+and the push both the test and release trees using:
- $ git push origin test
-and
- $ git push origin release
+ $ git push mytree
+
+or push just one of the test and release branches using:
+
+ $ git push mytree test
+or
+ $ git push mytree release
Now to apply some patches from the community. Think of a short
snappy name for a branch to hold this patch (or related group of
$ rm .git/refs/heads/branchname
+Some changes are so trivial that it is not necessary to create a separate
+branch and then merge into each of the test and release branches. For
+these changes, just apply directly to the "release" branch, and then
+merge that into the "test" branch.
+
To create diffstat and shortlog summaries of changes to include in a "please
pull" request to Linus you can use:
and
$ git-whatchanged release ^linus | git-shortlog
+
+Here are some of the scripts that I use to simplify all this even further.
+
+==== update script ====
+# Update a branch in my GIT tree. If the branch to be updated
+# is "linus", then pull from kernel.org. Otherwise merge local
+# linus branch into test|release branch
+
+case "$1" in
+test|release)
+ git checkout $1 && git resolve $1 linus "Auto-update from upstream"
+ ;;
+linus)
+ before=$(cat .git/refs/heads/linus)
+ git fetch linus
+ after=$(cat .git/refs/heads/linus)
+ if [ $before != $after ]
+ then
+ git-whatchanged $after ^$before | git-shortlog
+ fi
+ ;;
+*)
+ echo "Usage: $0 linus|test|release" 1>&2
+ exit 1
+ ;;
+esac
+
+==== merge script ====
+# Merge a branch into either the test or release branch
+
+pname=$0
+
+usage()
+{
+ echo "Usage: $pname branch test|release" 1>&2
+ exit 1
+}
+
+if [ ! -f .git/refs/heads/"$1" ]
+then
+ echo "Can't see branch <$1>" 1>&2
+ usage
+fi
+
+case "$2" in
+test|release)
+ if [ $(git-rev-list $1 ^$2 | wc -c) -eq 0 ]
+ then
+ echo $1 already merged into $2 1>&2
+ exit 1
+ fi
+ git checkout $2 && git resolve $2 $1 "Pull $1 into $2 branch"
+ ;;
+*)
+ usage
+ ;;
+esac
+
+==== status script ====
+# report on status of my ia64 GIT tree
+
+gb=$(tput setab 2)
+rb=$(tput setab 1)
+restore=$(tput setab 9)
+
+if [ `git-rev-list release ^test | wc -c` -gt 0 ]
+then
+ echo $rb Warning: commits in release that are not in test $restore
+ git-whatchanged release ^test
+fi
+
+for branch in `ls .git/refs/heads`
+do
+ if [ $branch = linus -o $branch = test -o $branch = release ]
+ then
+ continue
+ fi
+
+ echo -n $gb ======= $branch ====== $restore " "
+ status=
+ for ref in test release linus
+ do
+ if [ `git-rev-list $branch ^$ref | wc -c` -gt 0 ]
+ then
+ status=$status${ref:0:1}
+ fi
+ done
+ case $status in
+ trl)
+ echo $rb Need to pull into test $restore
+ ;;
+ rl)
+ echo "In test"
+ ;;
+ l)
+ echo "Waiting for linus"
+ ;;
+ "")
+ echo $rb All done $restore
+ ;;
+ *)
+ echo $rb "<$status>" $restore
+ ;;
+ esac
+ git-whatchanged $branch ^linus | git-shortlog
+done