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Another good resource is Think Like A Git, a site who's main page states "Git shouldn't be so hard to learn."
Finally, Git Best Practices is an excellent page with tons of information, overview and links to other good resources about best-practice usage of git.
Git Merge Strategies
Git has many "strategies" you can use while merging. Read the following carefully:
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|---|---|---|
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MERGE STRATEGIES
----------------
The merge mechanism ('git-merge' and 'git-pull' commands) allows the
backend 'merge strategies' to be chosen with `-s` option. Some strategies
can also take their own options, which can be passed by giving `-X<option>`
arguments to 'git-merge' and/or 'git-pull'.
resolve::
This can only resolve two heads (i.e. the current branch
and another branch you pulled from) using a 3-way merge
algorithm. It tries to carefully detect criss-cross
merge ambiguities and is considered generally safe and
fast.
recursive::
This can only resolve two heads using a 3-way merge
algorithm. When there is more than one common
ancestor that can be used for 3-way merge, it creates a
merged tree of the common ancestors and uses that as
the reference tree for the 3-way merge. This has been
reported to result in fewer merge conflicts without
causing mis-merges by tests done on actual merge commits
taken from Linux 2.6 kernel development history.
Additionally this can detect and handle merges involving
renames. This is the default merge strategy when
pulling or merging one branch.
+
The 'recursive' strategy can take the following options:
ours;;
This option forces conflicting hunks to be auto-resolved cleanly by
favoring 'our' version. Changes from the other tree that do not
conflict with our side are reflected to the merge result.
+
This should not be confused with the 'ours' merge strategy, which does not
even look at what the other tree contains at all. It discards everything
the other tree did, declaring 'our' history contains all that happened in it.
theirs;;
This is opposite of 'ours'.
patience;;
With this option, 'merge-recursive' spends a little extra time
to avoid mismerges that sometimes occur due to unimportant
matching lines (e.g., braces from distinct functions). Use
this when the branches to be merged have diverged wildly.
See also linkgit:git-diff[1] `--patience`.
ignore-space-change;;
ignore-all-space;;
ignore-space-at-eol;;
Treats lines with the indicated type of whitespace change as
unchanged for the sake of a three-way merge. Whitespace
changes mixed with other changes to a line are not ignored.
See also linkgit:git-diff[1] `-b`, `-w`, and
`--ignore-space-at-eol`.
+
* If 'their' version only introduces whitespace changes to a line,
'our' version is used;
* If 'our' version introduces whitespace changes but 'their'
version includes a substantial change, 'their' version is used;
* Otherwise, the merge proceeds in the usual way.
renormalize;;
This runs a virtual check-out and check-in of all three stages
of a file when resolving a three-way merge. This option is
meant to be used when merging branches with different clean
filters or end-of-line normalization rules. See "Merging
branches with differing checkin/checkout attributes" in
linkgit:gitattributes[5] for details.
no-renormalize;;
Disables the `renormalize` option. This overrides the
`merge.renormalize` configuration variable.
rename-threshold=<n>;;
Controls the similarity threshold used for rename detection.
See also linkgit:git-diff[1] `-M`.
subtree[=<path>];;
This option is a more advanced form of 'subtree' strategy, where
the strategy makes a guess on how two trees must be shifted to
match with each other when merging. Instead, the specified path
is prefixed (or stripped from the beginning) to make the shape of
two trees to match.
octopus::
This resolves cases with more than two heads, but refuses to do
a complex merge that needs manual resolution. It is
primarily meant to be used for bundling topic branch
heads together. This is the default merge strategy when
pulling or merging more than one branch.
ours::
This resolves any number of heads, but the resulting tree of the
merge is always that of the current branch head, effectively
ignoring all changes from all other branches. It is meant to
be used to supersede old development history of side
branches. Note that this is different from the -Xours option to
the 'recursive' merge strategy.
subtree::
This is a modified recursive strategy. When merging trees A and
B, if B corresponds to a subtree of A, B is first adjusted to
match the tree structure of A, instead of reading the trees at
the same level. This adjustment is also done to the common
ancestor tree. |
Git and Eclipse
The latest version of Eclipse (indigo) comes with a URL for installing EGit. The EGit eclipse plugin provides eclipse with git support. A good place to start is the User's guild: http://wiki.eclipse.org/EGit/User_Guide.
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This is a compilation of some potentially useful git commands and/or aliases
1) Command Line commit graph
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PITFALL - must be run against every new checkout of the repository. I'm not sure if this means when you swap branches, but I suspect it may.
3) Ignoring whitespace changes when a rebase fails
Sometimes when you go to do a rebase that should be simple, git fails and tells you that the entire file has changed. It may output something like this.
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|---|
M pom.xml
<stdin>:15: trailing whitespace.
<groupId>log4j</groupId>
<stdin>:16: trailing whitespace.
<artifactId>apache-log4j-extras</artifactId>
<stdin>:17: trailing whitespace.
<version>1.1</version>
<stdin>:18: trailing whitespace.
</dependency>
<stdin>:19: trailing whitespace.
warning: squelched 1 whitespace error
warning: 6 lines add whitespace errors. |
This indicates that there have been whitespace changes. Unless you're using python however, these probably aren't relevant and letting git sort them out will work fine. To do this, pass the --ignore-whitespace option to rebase.
Alternatively, you could run this command to make it so whitespace is automatically ignored unless you want it to be relevant:
| Code Block |
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git config --global apply.ignorewhitespace change |
This is documented under the git-apply man page.
4) Recovering from terrible things happening to your git repository
Check out this blog post: http://www.programblings.com/2008/06/07/the-illustrated-guide-to-recovering-lost-commits-with-git/
Not really a git trick, but a github convenience. Repositories on github can have their default branch specified. This is useful to reduce drag and prevent worry, by making github automatically select the correct branch for a pull request to go into.
Simply go to your github repository's page and click the admin link (hint: you need admin privileges), right near the top of the page there's a setting called "Default Branch".