I've only just started to use Git and think it is wonderful, however I'm a little confused over what the merge command does.
Let us say we have a working project in the branch "A".
I go home and make changes to this branch and save it as "B". Another programmer makes changes to "A" and saves it as "C".
Is there a way to merge the two branches "B" and "C" together, then commit the changes as a new branch, say "D"?
Or am missing the point of 'merge'?
merge is used to bring two (or more) branches together.
A little example:
$ # on branch A:
$ # create new branch B
$ git checkout -b B
$ # edit files
$ git commit -am "commit on branch B"
$ # create new branch C from A
$ git checkout -b C A
$ # edit files
$ git commit -am "commit on branch C"
$ # go back to branch A
$ git checkout A
$ # edit files
$ git commit -am "commit on branch A"
So now there are three separate branches (namely A, B, and C) with different heads.
To get the changes from B and C back to A, check out A (already done in this example) and then use the merge command:
$ # create an octopus merge
$ git merge B C
Your history will then look something like this:
…-o-o-x-------A
|\ /|
| B---/ |
\ /
C---/
Alternatively, to create "regular" merge commits (with exactly two parents each), run git merge twice for each branch that you want to merge:
$ git merge B
$ git merge C
To get a history similar to:
…-o-o-x-------M-A
|\ / /
| B---/ /
\ /
C---/
If you want to merge across repository/computer borders, have a look at git pull command, e.g. from the PC with branch A (this example will create two new commits):
$ # pull branch B
$ git pull ssh://host/… B
$ # pull branch C
$ git pull ssh://host/… C