log command can help us figure
out what is happening on each.
-
+
+ First we'll create a new branch to add the Erlang programming language + Hello World example - we want to do this in a branch so that we don't + muddy up our stable branch with code that may not work for a while so we + can cleanly switch in and out of it.
+ ++$ git checkout -b erlang +Switched to a new branch 'erlang' +$ vim erlang_hw.erl +$ git add erlang_hw.erl +$ git commit -m 'added erlang' +[erlang ab5ab4c] added erlang + 1 files changed, 5 insertions(+), 0 deletions(-) + create mode 100644 erlang_hw.erl ++ +
Since we're having fun playing in functional programming languages we + get caught up in it and also add a Haskell example program while still in + the branch named 'erlang'.
+ ++$ vim haskell.hs +$ git add haskell.hs +$ git commit -m 'added haskell' +[erlang 1834130] added haskell + 1 files changed, 4 insertions(+), 0 deletions(-) + create mode 100644 haskell.hs ++ +
Finally, we decide that we want to change the class name of our Ruby + program back to the way it was. So, we can go back to the master branch + and change that and we decide to just commit it directly in the master + branch instead of creating another branch.
+ ++$ git checkout master +Switched to branch 'master' +$ ls +README ruby.rb +$ vim ruby.rb +$ git commit -am 'reverted to old class name' +[master 594f90b] reverted to old class name + 1 files changed, 2 insertions(+), 2 deletions(-) ++ +
So, now say we don't work on the project for a while, we have other
+ things to do. When we come back we want to know what the 'erlang' branch
+ is all about and where we've left off on the master branch. Just by looking
+ at the branch name, we can't know that we made Haskell changes in there, but
+ using git log we easily can. If you give Git a branch name,
+ it will show you just the commits that are "reachable" in the history of
+ that branch, that is the commits that influenced the final snapshot.
+$ git log --oneline erlang
+1834130 added haskell
+ab5ab4c added erlang
+8d585ea Merge branch 'fix_readme'
+3cbb6aa fixed readme title differently
+3ac015d fixed readme title
+558151a Merge branch 'change_class'
+b7ae93b added from ruby
+3467b0a changed the class name
+17f4acf first commit
+
+
+ This way, it's pretty easy to see that we have Haskell code included in + the branch (as I've highlighted). What is even cooler is that we can + easily tell Git that we only are interested in the commits that are + reachable in one branch that are not reachable in another, in other words + which commits are unique to a branch in comparison to another. +
+ +
+ In this case if we are interested in merging in the 'erlang' branch we
+ want to see what commits are going to effect our snapshot when we do
+ that merge. The way we tell Git that is by putting a ^ in
+ front of the branch that we don't want to see. For instance, if we want
+ to see the commits that are in the 'erlang' branch that are not in the
+ 'master' branch, we can do erlang ^master, or vice versa.
+
+$ git log --oneline erlang ^master +1834130 added haskell +ab5ab4c added erlang +$ git log --oneline master ^erlang +594f90b reverted to old class name ++ +
This gives us a nice, simple branch management tool. It allows us to + easily see what commits are unique to which branches so we know what + we're missing and what we would be merging in if we were to do a merge. +
In a nutshell you use git log to list out the commit