Changes for page Git

Last modified by Richard Kreissig on 2025/01/30 12:03

From version < 39.1 >

edited by msp
on 2012/10/16 15:10

To version < 44.1 >

edited by msp
on 2012/10/16 16:42

Change comment: There is no comment for this version

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@@ -2,11 +2,11 @@
  More in-depth Git documentation can be found on the [[official home page>>url:http://git-scm.com/documentation||shape="rect"]], which mentions books, videos, and links to other tutorials and references. Furthermore, the shell command {{code language="none"}}git help{{/code}} lists the most commonly used Git commands, and {{code language="none"}}git help <command>{{/code}} gives very detailed documentation for the specified Git command.
--==== Contents ====
++=== Contents ===
--{{toc style="circle" maxLevel="3"/}}
++{{toc style="circle" maxLevel="2"/}}
  = Creating Commits =
@@ -132,7 +132,7 @@
  = Branching and Merging =
--In the previous section you have created two commits on the default branch, which is named {{code language="none"}}master{{/code}}. Now you will create a new branch and commit there, thus adding complexity to the commit graph.
++In the previous section you have created two commits on the default branch, which is named {{code language="none"}}master{{/code}}. Now you will create a new branch and commit there, thus adding complexity to the commit graph. In general, you may create as many local branches as you like, since they are simple to use and can be a great tool to structure your work.
 . (((
  Create a branch with name //sketches//:
@@ -378,7 +378,7 @@
  $ cd turing2
  {{/noformat}}
--The {{code language="none"}}clone{{/code}} command automatically creates a remote named {{code language="none"}}origin{{/code}} in the new local repository, which is set to the given URL.
++The {{code language="none"}}clone{{/code}} command automatically creates a remote named {{code language="none"}}origin{{/code}} in the new local repository, which is set to the given URL. You will use this second clone to simulate another user with access to the repository.
  )))
 . Edit the file {{code language="none"}}examples.txt{{/code}} in the new clone ({{code language="none"}}turing2{{/code}}): replace {{code language="none"}}"a"{{/code}} in line 6 by {{code language="none"}}"c"{{/code}} and correct the tape representations in lines 9, 14, and 19 accordingly. Commit the change.
 . (((
@@ -545,10 +545,10 @@
 f686..b58ded7  master -> master
  {{/noformat}}
--While {{code language="none"}}pull{{/code}} performs a {{code language="none"}}fetch{{/code}} and a {{code language="none"}}merge{{/code}}, {{code language="none"}}push{{/code}} transfers the new merged branch to the server. Note that during the merge operation conflicts can occur. In that case you have to resolve them and commit the changes before you can push.
++While {{code language="none"}}pull{{/code}} performs a {{code language="none"}}fetch{{/code}} and a {{code language="none"}}merge{{/code}}, {{code language="none"}}push{{/code}} transfers the new merged branch to the server. Note that during the merge operation conflicts can occur. In that case you have to resolve them and commit the changes before you can push. When used without parameters like shown above, {{code language="none"}}pull{{/code}} lookes in {{code language="none"}}.git/config{{/code}} to determine which branches to pull from which remotes.
  )))
 . (((
--In order to check out the {{code language="none"}}sketches{{/code}} branch, which was previously pushed to the server, simply type the following command:
++In order to check out the {{code language="none"}}sketches{{/code}} branch locally, which was previously pushed to the server, simply type the following command:
  {{noformat}}
  $ git checkout sketches
@@ -556,7 +556,7 @@
  Switched to a new branch 'sketches'
  {{/noformat}}
--This branch can be pushed and pulled with the server in the same way as you did for the {{code language="none"}}master{{/code}} branch.
++This branch can be pushed and pulled with the server in the same way as you did for the {{code language="none"}}master{{/code}} branch. Never check out {{code language="none"}}origin/sketches{{/code}}, since that is a remote tracking branch!
  )))
  The {{code language="none"}}master{{/code}} branch should look like this:
@@ -563,4 +563,116 @@
  [[image:attach:turing-graph-02.png]]
--
++= Other Useful Commands =
++
++This section contains optional steps that you don't need to push online, but can be useful for you to learn.
++
++=== Ignoring Files ===
++
++While working on his Machine, Alan Turing has produced a temporary file {{code language="none"}}experiments.tmp{{/code}}, which he does not want to commit in the repository:
++
++{{noformat}}
++$ git status
++# On branch master
++# Untracked files:
++#   (use "git add <file>..." to include in what will be committed)
++#
++#       experiments.tmp
++nothing added to commit but untracked files present (use "git add" to track)
++{{/noformat}}
++
++Since the extra mention of that file can make Git's status reports unnecessarily cluttered, Alan wants to ignore it permanently. Help him by adding a {{code language="none"}}.gitignore{{/code}} file to the repository:
++
++{{noformat}}
++$ echo "*.tmp" > .gitignore
++$ git add .gitignore
++$ git commit -m "added ignore file"
++[master 738ce4c] added ignore file
++ 1 files changed, 1 insertions(+), 0 deletions(-)
++ create mode 100644 .gitignore
++$ git status
++# On branch master
++# Your branch is ahead of 'origin/master' by 1 commit.
++#
++nothing to commit (working directory clean)
++{{/noformat}}
++
++Now the experiments.tmp{{code language="none"}}{{/code}} file is not considered when viewing the status. You can add arbitrary file name patterns to the {{code language="none"}}.gitignore{{/code}} file; for example it is a good idea to ignore {{code language="none"}}*.class{{/code}}, which are binary files generated for Java projects.
++
++=== Discarding Changes ===
++
++While working on his Machine, Alan Turing has made some changes to notes.txt that he later found out to be nonsense:
++
++{{noformat}}
++$ git status
++# On branch master
++# Changed but not updated:
++#   (use "git add <file>..." to update what will be committed)
++#   (use "git checkout -- <file>..." to discard changes in working directory)
++#
++#       modified:   notes.txt
++#
++no changes added to commit (use "git add" and/or "git commit -a")
++{{/noformat}}
++
++Help Alan by restoring the last committed state of that file:
++
++{{noformat}}
++$ git checkout HEAD notes.txt
++$ git status
++# On branch master
++nothing to commit (working directory clean)
++{{/noformat}}
++
++Instead of HEAD, which is the last commit on the current branch, you can also name any other branch or commit hash. In that case you would have to commit the change to make it permanent. While resolving conflicts it is possible to use {{code language="none"}}--theirs{{/code}} or {{code language="none"}}--ours{{/code}} instead of HEAD, which replaces the whole content of the respective file by their version (the one on the remote branch) or our version (the one on the current branch).
++
++A more brute-force option is using the {{code language="none"}}reset{{/code}} command:
++
++{{noformat}}
++$ git reset --hard
++HEAD is now at b58ded7 Merge branch 'master' of git.rtsys.informatik.uni-kiel.de:personal-msp/turing
++{{/noformat}}
++
++This resets //all// changes to the working copy to the head of the current branch, so use it with caution! However, {{code language="none"}}reset{{/code}} does not remove unstaged files. In order to do that in one command, use {{code language="none"}}clean{{/code}}:
++
++{{noformat}}
++$ git status
++# On branch master
++# Untracked files:
++#   (use "git add <file>..." to include in what will be committed)
++#
++#       test1.tmp
++#       test2.tmp
++nothing added to commit but untracked files present (use "git add" to track)
++$ git clean -f
++Removing test1.tmp
++Removing test2.tmp
++{{/noformat}}
++
++=== Rebasing ===
++
++Consider the following situation:
++
++[[image:attach:turing-graph-03.png]]
++
++If you want to merge the changes made on the {{code language="none"}}master{{/code}} branch into the {{code language="none"}}sketches{{/code}} branch, the normal way is to use the {{code language="none"}}merge{{/code}} command and create a merge commit. However, the {{code language="none"}}rebase{{/code}} command gives an interesting alternative to that: it reapplies all commits done in the current branch starting from a given reference.
++
++{{noformat}}
++$ git rebase master
++First, rewinding head to replay your work on top of it...
++Applying: added another example
++Applying: state transitions
++Using index info to reconstruct a base tree...
++Falling back to patching base and 3-way merge...
++Auto-merging notes.txt
++{{/noformat}}
++
++Afterwards the commit graph looks like this:
++
++[[image:attach:turing-graph-04.png]]
++
++The two commits made in {{code language="none"}}sketches{{/code}} are reapplied starting from the head of the {{code language="none"}}master{{/code}} branch. The resulting structure of commits is much cleaner than before. rebase{{code language="none"}}{{/code}} even allows to squeeze multiple commits into one. Note that in this example a merge conflict had to be resolved in the same way as it was done in Section "Branching and Merging"; instead of committing the resolved file, the rebase command is resumed with {{code language="none"}}git rebase --continue{{/code}}.
++
++{{warning}}
++Never rebase a branch that is already pushed online! Due to the structural change the rebased branch is no longer compatible with the previous one, and pushing it will fail, since fast-forward merge is not possible.
++{{/warning}}

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@@ -1,1 +1,1 @@
--2982161
++2982174

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@@ -1,1 +1,1 @@
--https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/WS12EclPract/pages/2982161/Git
++https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/WS12EclPract/pages/2982174/Git

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