git/Documentation/scalar.txt
Victoria Dye 7b5c93c6c6 scalar: include in standard Git build & installation
Move 'scalar' out of 'contrib/' and into the root of the Git tree. The goal
of this change is to build 'scalar' as part of the standard Git build &
install processes.

This patch includes both the physical move of Scalar's files out of
'contrib/' ('scalar.c', 'scalar.txt', and 't9xxx-scalar.sh'), and the
changes to the build definitions in 'Makefile' and 'CMakelists.txt' to
accommodate the new program.

At a high level, Scalar is built so that:
- there is a 'scalar-objs' target (similar to those created in 029bac01a8
  (Makefile: add {program,xdiff,test,git,fuzz}-objs & objects targets,
  2021-02-23)) for debugging purposes.
- it appears in the root of the install directory (rather than the
  gitexecdir).
- it is included in the 'bin-wrappers/' directory for use in tests.
- it receives a platform-specific executable suffix (e.g., '.exe'), if
  applicable.
- 'scalar.txt' is installed as 'man1' documentation.
- the 'clean' target removes the 'scalar' executable.

Additionally, update the root level '.gitignore' file to ignore the Scalar
executable.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-02 10:02:55 -07:00

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scalar(1)
=========
NAME
----
scalar - A tool for managing large Git repositories
SYNOPSIS
--------
[verse]
scalar clone [--single-branch] [--branch <main-branch>] [--full-clone] <url> [<enlistment>]
scalar list
scalar register [<enlistment>]
scalar unregister [<enlistment>]
scalar run ( all | config | commit-graph | fetch | loose-objects | pack-files ) [<enlistment>]
scalar reconfigure [ --all | <enlistment> ]
scalar diagnose [<enlistment>]
scalar delete <enlistment>
DESCRIPTION
-----------
Scalar is a repository management tool that optimizes Git for use in large
repositories. Scalar improves performance by configuring advanced Git settings,
maintaining repositories in the background, and helping to reduce data sent
across the network.
An important Scalar concept is the enlistment: this is the top-level directory
of the project. It usually contains the subdirectory `src/` which is a Git
worktree. This encourages the separation between tracked files (inside `src/`)
and untracked files, such as build artifacts (outside `src/`). When registering
an existing Git worktree with Scalar whose name is not `src`, the enlistment
will be identical to the worktree.
The `scalar` command implements various subcommands, and different options
depending on the subcommand. With the exception of `clone`, `list` and
`reconfigure --all`, all subcommands expect to be run in an enlistment.
The following options can be specified _before_ the subcommand:
-C <directory>::
Before running the subcommand, change the working directory. This
option imitates the same option of linkgit:git[1].
-c <key>=<value>::
For the duration of running the specified subcommand, configure this
setting. This option imitates the same option of linkgit:git[1].
COMMANDS
--------
Clone
~~~~~
clone [<options>] <url> [<enlistment>]::
Clones the specified repository, similar to linkgit:git-clone[1]. By
default, only commit and tree objects are cloned. Once finished, the
worktree is located at `<enlistment>/src`.
+
The sparse-checkout feature is enabled (except when run with `--full-clone`)
and the only files present are those in the top-level directory. Use
`git sparse-checkout set` to expand the set of directories you want to see,
or `git sparse-checkout disable` to expand to all files (see
linkgit:git-sparse-checkout[1] for more details). You can explore the
subdirectories outside your sparse-checkout by using `git ls-tree
HEAD[:<directory>]`.
-b <name>::
--branch <name>::
Instead of checking out the branch pointed to by the cloned
repository's HEAD, check out the `<name>` branch instead.
--[no-]single-branch::
Clone only the history leading to the tip of a single branch, either
specified by the `--branch` option or the primary branch remote's
`HEAD` points at.
+
Further fetches into the resulting repository will only update the
remote-tracking branch for the branch this option was used for the initial
cloning. If the HEAD at the remote did not point at any branch when
`--single-branch` clone was made, no remote-tracking branch is created.
--[no-]full-clone::
A sparse-checkout is initialized by default. This behavior can be
turned off via `--full-clone`.
List
~~~~
list::
List enlistments that are currently registered by Scalar. This
subcommand does not need to be run inside an enlistment.
Register
~~~~~~~~
register [<enlistment>]::
Adds the enlistment's repository to the list of registered repositories
and starts background maintenance. If `<enlistment>` is not provided,
then the enlistment associated with the current working directory is
registered.
+
Note: when this subcommand is called in a worktree that is called `src/`, its
parent directory is considered to be the Scalar enlistment. If the worktree is
_not_ called `src/`, it itself will be considered to be the Scalar enlistment.
Unregister
~~~~~~~~~~
unregister [<enlistment>]::
Remove the specified repository from the list of repositories
registered with Scalar and stop the scheduled background maintenance.
Run
~~~
scalar run ( all | config | commit-graph | fetch | loose-objects | pack-files ) [<enlistment>]::
Run the given maintenance task (or all tasks, if `all` was specified).
Except for `all` and `config`, this subcommand simply hands off to
linkgit:git-maintenance[1] (mapping `fetch` to `prefetch` and
`pack-files` to `incremental-repack`).
+
These tasks are run automatically as part of the scheduled maintenance,
as soon as the repository is registered with Scalar. It should therefore
not be necessary to run this subcommand manually.
+
The `config` task is specific to Scalar and configures all those
opinionated default settings that make Git work more efficiently with
large repositories. As this task is run as part of `scalar clone`
automatically, explicit invocations of this task are rarely needed.
Reconfigure
~~~~~~~~~~~
After a Scalar upgrade, or when the configuration of a Scalar enlistment
was somehow corrupted or changed by mistake, this subcommand allows to
reconfigure the enlistment.
With the `--all` option, all enlistments currently registered with Scalar
will be reconfigured. Use this option after each Scalar upgrade.
Diagnose
~~~~~~~~
diagnose [<enlistment>]::
When reporting issues with Scalar, it is often helpful to provide the
information gathered by this command, including logs and certain
statistics describing the data shape of the current enlistment.
+
The output of this command is a `.zip` file that is written into
a directory adjacent to the worktree in the `src` directory.
Delete
~~~~~~
delete <enlistment>::
This subcommand lets you delete an existing Scalar enlistment from your
local file system, unregistering the repository.
SEE ALSO
--------
linkgit:git-clone[1], linkgit:git-maintenance[1].
GIT
---
Part of the linkgit:git[1] suite