X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=Documentation%2Fuser-manual.txt;h=1c49e6995b42e42f1aba4e7b24d073e50c3b5234;hb=3a81b9f571a6b7edd83b3d5f27c3c95d9b1c9d5c;hp=ffd673ec335c3d85d6815dcfdc3e1bfd019f8551;hpb=31930b5beece8ff86f823b62cf0937e73e9494fa;p=git.git diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index ffd673ec3..1c49e6995 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -288,21 +288,22 @@ collection of files. It stores the history as a compressed collection of interrelated snapshots (versions) of the project's contents. -A single git repository may contain multiple branches. Each branch -is a bookmark referencing a particular point in the project history. -The gitlink:git-branch[1] command shows you the list of branches: +A single git repository may contain multiple branches. It keeps track +of them by keeping a list of <> which reference the +latest version on each branch; the gitlink:git-branch[1] command shows +you the list of branch heads: ------------------------------------------------ $ git branch * master ------------------------------------------------ -A freshly cloned repository contains a single branch, named "master", -and the working directory contains the version of the project -referred to by the master branch. +A freshly cloned repository contains a single branch head, named +"master", and working directory is initialized to the state of +the project referred to by "master". -Most projects also use tags. Tags, like branches, are references -into the project's history, and can be listed using the +Most projects also use <>. Tags, like heads, are +references into the project's history, and can be listed using the gitlink:git-tag[1] command: ------------------------------------------------ @@ -320,9 +321,9 @@ v2.6.13 ------------------------------------------------ Tags are expected to always point at the same version of a project, -while branches are expected to advance as development progresses. +while heads are expected to advance as development progresses. -Create a new branch pointing to one of these versions and check it +Create a new branch head pointing to one of these versions and check it out using gitlink:git-checkout[1]: ------------------------------------------------ @@ -346,10 +347,10 @@ the current branch to point at v2.6.17 instead, with $ git reset --hard v2.6.17 ------------------------------------------------ -Note that if the current branch was your only reference to a +Note that if the current branch head was your only reference to a particular point in history, then resetting that branch may leave you -with no way to find the history it used to point to; so use this -command carefully. +with no way to find the history it used to point to; so use this command +carefully. Understanding History: Commits ------------------------------ @@ -437,11 +438,14 @@ We will sometimes represent git history using diagrams like the one below. Commits are shown as "o", and the links between them with lines drawn with - / and \. Time goes left to right: + +................................................ o--o--o <-- Branch A / o--o--o <-- master \ o--o--o <-- Branch B +................................................ If we need to talk about a particular commit, the character "o" may be replaced with another letter or number. @@ -449,17 +453,15 @@ be replaced with another letter or number. Understanding history: What is a branch? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Though we've been using the word "branch" to mean a kind of reference -to a particular commit, the word branch is also commonly used to -refer to the line of commits leading up to that point. In the -example above, git may think of the branch named "A" as just a -pointer to one particular commit, but we may refer informally to the -line of three commits leading up to that point as all being part of +When we need to be precise, we will use the word "branch" to mean a line +of development, and "branch head" (or just "head") to mean a reference +to the most recent commit on a branch. In the example above, the branch +head named "A" is a pointer to one particular commit, but we refer to +the line of three commits leading up to that point as all being part of "branch A". -If we need to make it clear that we're just talking about the most -recent commit on the branch, we may refer to that commit as the -"head" of the branch. +However, when no confusion will result, we often just use the term +"branch" both for branches and for branch heads. Manipulating branches --------------------- @@ -601,8 +603,8 @@ a new stanza: $ cat .git/config ... [remote "linux-nfs"] - url = git://linux-nfs.org/~bfields/git.git - fetch = +refs/heads/*:refs/remotes/linux-nfs-read/* + url = git://linux-nfs.org/pub/nfs-2.6.git + fetch = +refs/heads/*:refs/remotes/linux-nfs/* ... ------------------------------------------------- @@ -1133,17 +1135,9 @@ modified in two different ways in the remote branch and the local branch--then you are warned; the output may look something like this: ------------------------------------------------- -$ git pull . next -Trying really trivial in-index merge... -fatal: Merge requires file-level merging -Nope. -Merging HEAD with 77976da35a11db4580b80ae27e8d65caf5208086 -Merging: -15e2162 world -77976da goodbye -found 1 common ancestor(s): -d122ed4 initial -Auto-merging file.txt +$ git merge next + 100% (4/4) done +Auto-merged file.txt CONFLICT (content): Merge conflict in file.txt Automatic merge failed; fix conflicts and then commit the result. ------------------------------------------------- @@ -1439,7 +1433,7 @@ modifying the working directory, you can do that with gitlink:git-show[1]: ------------------------------------------------- -$ git show HEAD^ path/to/file +$ git show HEAD^:path/to/file ------------------------------------------------- which will display the given version of the file. @@ -1703,7 +1697,7 @@ If you and maintainer both have accounts on the same machine, then then you can just pull changes from each other's repositories directly; note that all of the commands (gitlink:git-clone[1], git-fetch[1], git-pull[1], etc.) that accept a URL as an argument -will also accept a local file patch; so, for example, you can +will also accept a local directory name; so, for example, you can use ------------------------------------------------- @@ -1936,25 +1930,29 @@ $ git commit You have performed no merges into mywork, so it is just a simple linear sequence of patches on top of "origin": - +................................................ o--o--o <-- origin \ o--o--o <-- mywork +................................................ Some more interesting work has been done in the upstream project, and "origin" has advanced: +................................................ o--o--O--o--o--o <-- origin \ a--b--c <-- mywork +................................................ At this point, you could use "pull" to merge your changes back in; the result would create a new merge commit, like this: - +................................................ o--o--O--o--o--o <-- origin \ \ a--b--c--m <-- mywork +................................................ However, if you prefer to keep the history in mywork a simple series of commits without any merges, you may instead choose to use @@ -1971,9 +1969,11 @@ point at the latest version of origin, then apply each of the saved patches to the new mywork. The result will look like: +................................................ o--o--O--o--o--o <-- origin \ a'--b'--c' <-- mywork +................................................ In the process, it may discover conflicts. In that case it will stop and allow you to fix the conflicts; after fixing conflicts, use "git @@ -2081,24 +2081,30 @@ The primary problem with rewriting the history of a branch has to do with merging. Suppose somebody fetches your branch and merges it into their branch, with a result something like this: +................................................ o--o--O--o--o--o <-- origin \ \ t--t--t--m <-- their branch: +................................................ Then suppose you modify the last three commits: +................................................ o--o--o <-- new head of origin / o--o--O--o--o--o <-- old head of origin +................................................ If we examined all this history together in one repository, it will look like: +................................................ o--o--o <-- new head of origin / o--o--O--o--o--o <-- old head of origin \ \ t--t--t--m <-- their branch: +................................................ Git has no way of knowing that the new head is an updated version of the old head; it treats this situation exactly the same as it would if @@ -2159,9 +2165,11 @@ commit. Git calls this process a "fast forward". A fast forward looks something like this: +................................................ o--o--o--o <-- old head of the branch \ o--o--o <-- new head of the branch +................................................ In some cases it is possible that the new head will *not* actually be @@ -2169,11 +2177,11 @@ a descendant of the old head. For example, the developer may have realized she made a serious mistake, and decided to backtrack, resulting in a situation like: +................................................ o--o--o--o--a--b <-- old head of the branch \ o--o--o <-- new head of the branch - - +................................................ In this case, "git fetch" will fail, and print out a warning. @@ -3004,9 +3012,6 @@ confusing and scary messages, but it won't actually do anything bad. In contrast, running "git prune" while somebody is actively changing the repository is a *BAD* idea). -Glossary of git terms -===================== - include::glossary.txt[] Notes and todo list for this manual