diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt index bb4e6fbf59cb44700a4bf4f8b1bb750f934a927c..829b03201d0bc365983ed98034c3df284081c1d3 100644 --- a/Documentation/git-submodule.txt +++ b/Documentation/git-submodule.txt @@ -18,24 +18,44 @@ SYNOPSIS DESCRIPTION ----------- -Submodules are a special kind of tree entries which refer to a particular tree -state in another repository. The tree entry describes -the existence of a submodule with the given name and the exact revision that -should be used, while an entry in `.gitmodules` file gives the location of -the repository. - -When checked out, submodules will maintain their own independent repositories -within their directories; the only link between the submodule and the "parent -project" is the tree entry within the parent project mentioned above. - -This command will manage the tree entries and contents of the gitmodules file -for you, as well as inspecting the status of your submodules and updating them. -When adding a new submodule to the tree, the 'add' subcommand is to be used. -However, when pulling a tree containing submodules, these will not be checked -out by default; the 'init' and 'update' subcommands will maintain submodules -checked out and at appropriate revision in your working tree. You can inspect -the current status of your submodules using the 'submodule' subcommand and get -an overview of changes 'update' would perform using the 'summary' subcommand. +Submodules allow foreign repositories to be embedded within +a dedicated subdirectory of the source tree, always pointed +at a particular commit. + +They are not to be confused with remotes, which are meant mainly +for branches of the same project; submodules are meant for +different projects you would like to make part of your source tree, +while the history of the two projects still stays completely +independent and you cannot modify the contents of the submodule +from within the main project. +If you want to merge the project histories and want to treat the +aggregated whole as a single project from then on, you may want to +add a remote for the other project and use the 'subtree' merge strategy, +instead of treating the other project as a submodule. Directories +that come from both projects can be cloned and checked out as a whole +if you choose to go that route. + +Submodules are composed from a so-called `gitlink` tree entry +in the main repository that refers to a particular commit object +within the inner repository that is completely separate. +A record in the `.gitmodules` file at the root of the source +tree assigns a logical name to the submodule and describes +the default URL the submodule shall be cloned from. +The logical name can be used for overriding this URL within your +local repository configuration (see 'submodule init'). + +This command will manage the tree entries and contents of the +gitmodules file for you, as well as inspect the status of your +submodules and update them. +When adding a new submodule to the tree, the 'add' subcommand +is to be used. However, when pulling a tree containing submodules, +these will not be checked out by default; +the 'init' and 'update' subcommands will maintain submodules +checked out and at appropriate revision in your working tree. +You can briefly inspect the up-to-date status of your submodules +using the 'status' subcommand and get a detailed overview of the +difference between the index and checkouts using the 'summary' +subcommand. COMMANDS @@ -78,10 +98,15 @@ status:: repository. This command is the default command for 'git-submodule'. init:: - Initialize the submodules, i.e. register in .git/config each submodule - name and url found in .gitmodules. The key used in .git/config is - `submodule.$name.url`. This command does not alter existing information - in .git/config. + Initialize the submodules, i.e. register each submodule name + and url found in .gitmodules into .git/config. + The key used in .git/config is `submodule.$name.url`. + This command does not alter existing information in .git/config. + You can then customize the submodule clone URLs in .git/config + for your local setup and proceed to 'git submodule update'; + you can also just use 'git submodule update --init' without + the explicit 'init' step if you do not intend to customize + any submodule locations. update:: Update the registered submodules, i.e. clone missing submodules and