1git-checkout(1) 2=============== 3 4NAME 5---- 6git-checkout - Checkout and switch to a branch 7 8SYNOPSIS 9-------- 10[verse] 11'git-checkout' [-f] [-b <new_branch> [-l]] [-m] [<branch>] 12'git-checkout' [<branch>] <paths>... 13 14DESCRIPTION 15----------- 16 17When <paths> are not given, this command switches branches by 18updating the index and working tree to reflect the specified 19branch, <branch>, and updating HEAD to be <branch> or, if 20specified, <new_branch>. Using -b will cause <new_branch> to 21be created. 22 23When <paths> are given, this command does *not* switch 24branches. It updates the named paths in the working tree from 25the index file (i.e. it runs `git-checkout-index -f -u`). In 26this case, `-f` and `-b` options are meaningless and giving 27either of them results in an error. <branch> argument can be 28used to specify a specific tree-ish to update the index for the 29given paths before updating the working tree. 30 31 32OPTIONS 33------- 34-f:: 35 Force a re-read of everything. 36 37-b:: 38 Create a new branch named <new_branch> and start it at 39 <branch>. The new branch name must pass all checks defined 40 by gitlink:git-check-ref-format[1]. Some of these checks 41 may restrict the characters allowed in a branch name. 42 43-l:: 44 Create the new branch's ref log. This activates recording of 45 all changes to made the branch ref, enabling use of date 46 based sha1 expressions such as "<branchname>@{yesterday}". 47 48-m:: 49 If you have local modifications to one or more files that 50 are different between the current branch and the branch to 51 which you are switching, the command refuses to switch 52 branches in order to preserve your modifications in context. 53 However, with this option, a three-way merge between the current 54 branch, your working tree contents, and the new branch 55 is done, and you will be on the new branch. 56+ 57When a merge conflict happens, the index entries for conflicting 58paths are left unmerged, and you need to resolve the conflicts 59and mark the resolved paths with `git update-index`. 60 61<new_branch>:: 62 Name for the new branch. 63 64<branch>:: 65 Branch to checkout; may be any object ID that resolves to a 66 commit. Defaults to HEAD. 67+ 68When this parameter names a non-branch (but still a valid commit object), 69your HEAD becomes 'detached'. 70 71 72Detached HEAD 73------------- 74 75It is sometimes useful to be able to 'checkout' a commit that is 76not at the tip of one of your branches. The most obvious 77example is to check out the commit at a tagged official release 78point, like this: 79 80------------ 81$ git checkout v2.6.18 82------------ 83 84Earlier versions of git did not allow this and asked you to 85create a temporary branch using `-b` option, but starting from 86version 1.5.0, the above command 'detaches' your HEAD from the 87current branch and directly point at the commit named by the tag 88(`v2.6.18` in the above example). 89 90You can use usual git commands while in this state. You can use 91`git-reset --hard $othercommit` to further move around, for 92example. You can make changes and create a new commit on top of 93a detached HEAD. You can even create a merge by using `git 94merge $othercommit`. 95 96The state you are in while your HEAD is detached is not recorded 97by any branch (which is natural --- you are not on any branch). 98What this means is that you can discard your temporary commits 99and merges by switching back to an existing branch (e.g. `git 100checkout master`), and a later `git prune` or `git gc` would 101garbage-collect them. 102 103The command would refuse to switch back to make sure that you do 104not discard your temporary state by mistake when your detached 105HEAD is not pointed at by any existing ref. If you did want to 106save your state (e.g. "I was interested in the fifth commit from 107the top of 'master' branch", or "I made two commits to fix minor 108bugs while on a detached HEAD" -- and if you do not want to lose 109these facts), you can create a new branch and switch to it with 110`git checkout -b newbranch` so that you can keep building on 111that state, or tag it first so that you can come back to it 112later and switch to the branch you wanted to switch to with `git 113tag that_state; git checkout master`. On the other hand, if you 114did want to discard the temporary state, you can give `-f` 115option (e.g. `git checkout -f master`) to override this 116behaviour. 117 118 119EXAMPLES 120-------- 121 122. The following sequence checks out the `master` branch, reverts 123the `Makefile` to two revisions back, deletes hello.c by 124mistake, and gets it back from the index. 125+ 126------------ 127$ git checkout master <1> 128$ git checkout master~2 Makefile <2> 129$ rm -f hello.c 130$ git checkout hello.c <3> 131------------ 132+ 133<1> switch branch 134<2> take out a file out of other commit 135<3> restore hello.c from HEAD of current branch 136+ 137If you have an unfortunate branch that is named `hello.c`, this 138step would be confused as an instruction to switch to that branch. 139You should instead write: 140+ 141------------ 142$ git checkout -- hello.c 143------------ 144 145. After working in a wrong branch, switching to the correct 146branch would be done using: 147+ 148------------ 149$ git checkout mytopic 150------------ 151+ 152However, your "wrong" branch and correct "mytopic" branch may 153differ in files that you have locally modified, in which case, 154the above checkout would fail like this: 155+ 156------------ 157$ git checkout mytopic 158fatal: Entry 'frotz' not uptodate. Cannot merge. 159------------ 160+ 161You can give the `-m` flag to the command, which would try a 162three-way merge: 163+ 164------------ 165$ git checkout -m mytopic 166Auto-merging frotz 167------------ 168+ 169After this three-way merge, the local modifications are _not_ 170registered in your index file, so `git diff` would show you what 171changes you made since the tip of the new branch. 172 173. When a merge conflict happens during switching branches with 174the `-m` option, you would see something like this: 175+ 176------------ 177$ git checkout -m mytopic 178Auto-merging frotz 179merge: warning: conflicts during merge 180ERROR: Merge conflict in frotz 181fatal: merge program failed 182------------ 183+ 184At this point, `git diff` shows the changes cleanly merged as in 185the previous example, as well as the changes in the conflicted 186files. Edit and resolve the conflict and mark it resolved with 187`git update-index` as usual: 188+ 189------------ 190$ edit frotz 191$ git update-index frotz 192------------ 193 194 195Author 196------ 197Written by Linus Torvalds <torvalds@osdl.org> 198 199Documentation 200-------------- 201Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. 202 203GIT 204--- 205Part of the gitlink:git[7] suite 206