Git Tips

This entry is part 1 of 3 in the series Version Control

In the last seven months I learned git, working for a dozen of projects. On some of them I was the master&commander, on others I only set up the streams and let the young Jedi find the way to the delivery. Via trial and error I find out a bunch of userful commands.

I present here in order of priority, from the most important to the least…let’s start

 Userful monitoring / configuration  commands

  1. This is the first tip I suggest you:
    git config --global merge.ff false

    This configuration force git to register
    a commit object even if the merge is a fast forward merge.
    Git has a “smart” what of acting, consisting in not registering fast-forward merges. This can be very annoying if you try to track down an evil sith commiting random stuff on your system. Belive me. Sith are so evil!

  2. Find out what happen while you was on holidays…
    git whatchanged  master...my/great-release

    It is the most userful command to check differences between branches/tag/commits.
    If you have a huge project, you can also specify a directory like in

    git whatchanged  master...my/great-release test-scripts-dir

    The standard report is quite good, listing commit comment, and files.
    Even better if you want to recover the previous file’s version,  issue

    git show HEAD^1:parser/src/main/MyStuff.Java >OldStuff.java
    #For two version before try...
    git show HEAD^2:parser/src/main/MyStuff.Java
  3. Resync with remote is always a pain if you forget a branch…
    git remote update

    Without special configuration, this command will fetch updates for all your remotes.
    Very useful if you need to know the status of all your branches

  4. Logs are good, but logs with branch description are better:
    git log --decorate

    Will show you also the branches or the tag

  5. Sometimes you need to erase what you have just commited. An easy way to do it  is
    git reset --soft HEAD^

    This will revert your last commit, leaving it as “Changes to be committed”. Very userful if you do a wrong merge.For instance, if you are on branch “stable” and issue

    git pull origin instableStuff

    you will wrongly issue a merge of the  instableStuff into your stable branch. It is quite subtle.
    Sometimes there is a better option. It is called “revert”:

     git revert HEAD

    is better because will register a “revert” commit on the history, and it is useful when you already pushed your deadly stuff.

    Anyway, “git reflog” will keep in the trashcan the old commit, in case you need it. But be careful,m because reflog is compacted from time to time.

     

Team Caffeine Stats

git shortlog -s -n

Will give you fast stats on your team: is fomeone has a very huge commit rate, reduce free coffe meetings :)

Useful scripting commands

git ls-files
can be used with xargs to kill all your nasty binaries.
For instance
git ls-files workarea/workspace103 | grep /classes/ | xargs git rm
will save your days

Nice to know advices

  • Git 1.7.10 supports utf-8 encoding. I strongly encoruage you to use it instead of older version.
  • –dry-run option
    It is your best friend during a pull or a risky commit. Even if you are better then Yoda (or Linux) at git, you should definitely try it out sometimes.
  • git pull --rebase

    It should avoid merge linearizing input history.
    I am not sure it is a good idea, but can avoid repeating merges if you needn’t. Anyway, do a lot of testing before proceeding in this way.

Subversion to Git migration guide

This Good article
will save your days.

Known weird errors

  • can’t resolve proxy ‘null’ for https
    Do a

    $git var -l | grep http
    http.sslcainfo=/bin/curl-ca-bundle.crt
    http.proxy=

    If you have  the empty http.proxy config, here is the problem.

    Do a look at your $HOME/.gitconfig for the blank http.proxy  configuration, and zap it.

Here you can find other tips.
Hub is a replacement script for git, but I disagree with this approach: anyway, you can decide by yourself if it deserve your attention.

Proxy NTLM

Spesso capita di dover scaricare file al di fuori del browser: per esempio per installare software o per consentire ai propri programmi python/java/curl di effettuare delle azioni programmatiche

Se avete problemi con i proxy Microsoft (cosa abbastanza comune, vista la diffusione), su Internet trovate una soluzione:

Cntlm Authentication Proxy vi consente di avere un proxy integrato con il meccanismo non standard usato da Microsoft per autenticarsi. L’utility funziona molto bene, e potete integrarla con cygwin e/o python definendo la seguente variabile d’ambiente

HTTP_PROXY=http://127.0.0.1:3128

Grazie a questo trucco aggiuntivo, il proxy sarà usato da libcurl e da python.

Per Java invece può bastare lanciarlo con

java -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 classe.da.Lanciare

Celeste

Celeste

Celeste is a mail reading and organizing program. The name “Celeste” is a reference to an earlier mail reader named Baba, which was written at Xerox PARC by Steve Putz and John Maloney.

Nowadays, Celeste is maintained by Giovanni Giorgi (me).

Latest Feature

A new revision is planned for the end of September 2006, and code name will be “Sonic”.
Sonic will include a smart mailing-list filter and a better “leave message on server” option.
I implemented years ago an auto-filtering system in AppleScript.
The filtering engine used the
RFC2369 and some other tricks to detect yahoo mailing list.
Sonic will have also an auto-filter for google mailing list too.

The leave message on server option is quite bad now. It creates a lot
of duplicated messages.
The new implementation will avoid dowloading twice a message, using
a mix of messageId and timestamp to detect duplicated messages.

Version policy

I have found a misleading versions for celeste.
Celeste uses a “versionString” to mark a version in every sent email.
versionString labelled something like
2.currentChangeset.

As far as I started mantaining Celeste, we used a lower version (for example 1.23).

To avoid confusion I have started to renmbering all the stuff starting from revision 3.0.

Anyway, the version name is the first thing you should consider. I plan to do very few releases.

Celeste Auto Filter Capability (BETA)

Some busy users subscribe and unsubscribe to a lot of mailing list.
Managing them with filter is possibile, but can be done only by hand.
Worst, email programs tend to be very slow if a single folder is full of stuff,
and this can be true for Celeste too.

The Celeste Auto Filter option will enable a smart archiving system,
packing the email in seasons.
For instance “2006Q1-squeak-dev” will contain all the emails of squeak-dev of the first three month of 2006 (=the first quarter).

The Auto Filter will understand YahooGroups, Mailman and GoogleGroups mailing list, auto-dispatching them to the right category.
The filter will be enabled by default.

Downloads

You can find released versions on SqueakMap and development versions on SqueakSource.

Old resources: