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     NAME
          githooks - Hooks used by Git

     SYNOPSIS
          $GIT_DIR/hooks/* (or `git config core.hooksPath`/*)

     DESCRIPTION
          Hooks are programs you can place in a hooks directory to
          trigger actions at certain points in gitcqs execution. Hooks
          that doncqt have the executable bit set are ignored.

          By default the hooks directory is $GIT_DIR/hooks, but that
          can be changed via the core.hooksPath configuration variable
          (see git-config(1)).

          Before Git invokes a hook, it changes its working directory
          to either $GIT_DIR in a bare repository or the root of the
          working tree in a non-bare repository. An exception are
          hooks triggered during a push (pre-receive, update,
          post-receive, post-update, push-to-checkout) which are
          always executed in $GIT_DIR.

          Hooks can get their arguments via the environment,
          command-line arguments, and stdin. See the documentation for
          each hook below for details.

          git init may copy hooks to the new repository, depending on
          its configuration. See the "TEMPLATE DIRECTORY" section in
          git-init(1) for details. When the rest of this document
          refers to "default hooks" itcqs talking about the default
          template shipped with Git.

          The currently supported hooks are described below.

     HOOKS
        applypatch-msg
          This hook is invoked by git-am(1). It takes a single
          parameter, the name of the file that holds the proposed
          commit log message. Exiting with a non-zero status causes
          git am to abort before applying the patch.

          The hook is allowed to edit the message file in place, and
          can be used to normalize the message into some project
          standard format. It can also be used to refuse the commit
          after inspecting the message file.

          The default applypatch-msg hook, when enabled, runs the
          commit-msg hook, if the latter is enabled.

        pre-applypatch

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          This hook is invoked by git-am(1). It takes no parameter,
          and is invoked after the patch is applied, but before a
          commit is made.

          If it exits with non-zero status, then the working tree will
          not be committed after applying the patch.

          It can be used to inspect the current working tree and
          refuse to make a commit if it does not pass certain test.

          The default pre-applypatch hook, when enabled, runs the
          pre-commit hook, if the latter is enabled.

        post-applypatch
          This hook is invoked by git-am(1). It takes no parameter,
          and is invoked after the patch is applied and a commit is
          made.

          This hook is meant primarily for notification, and cannot
          affect the outcome of git am.

        pre-commit
          This hook is invoked by git-commit(1), and can be bypassed
          with the --no-verify option. It takes no parameters, and is
          invoked before obtaining the proposed commit log message and
          making a commit. Exiting with a non-zero status from this
          script causes the git commit command to abort before
          creating a commit.

          The default pre-commit hook, when enabled, catches
          introduction of lines with trailing whitespaces and aborts
          the commit when such a line is found.

          All the git commit hooks are invoked with the environment
          variable GIT_EDITOR=: if the command will not bring up an
          editor to modify the commit message.

          The default pre-commit hook, when enabled-and with the
          hooks.allownonascii config option unset or set to false-
          prevents the use of non-ASCII filenames.

        pre-merge-commit
          This hook is invoked by git-merge(1), and can be bypassed
          with the --no-verify option. It takes no parameters, and is
          invoked after the merge has been carried out successfully
          and before obtaining the proposed commit log message to make
          a commit. Exiting with a non-zero status from this script
          causes the git merge command to abort before creating a
          commit.

          The default pre-merge-commit hook, when enabled, runs the
          pre-commit hook, if the latter is enabled.

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          This hook is invoked with the environment variable
          GIT_EDITOR=: if the command will not bring up an editor to
          modify the commit message.

          If the merge cannot be carried out automatically, the
          conflicts need to be resolved and the result committed
          separately (see git-merge(1)). At that point, this hook will
          not be executed, but the pre-commit hook will, if it is
          enabled.

        prepare-commit-msg
          This hook is invoked by git-commit(1) right after preparing
          the default log message, and before the editor is started.

          It takes one to three parameters. The first is the name of
          the file that contains the commit log message. The second is
          the source of the commit message, and can be: message (if a
          -m or -F option was given); template (if a -t option was
          given or the configuration option commit.template is set);
          merge (if the commit is a merge or a .git/MERGE_MSG file
          exists); squash (if a .git/SQUASH_MSG file exists); or
          commit, followed by a commit object name (if a -c, -C or
          --amend option was given).

          If the exit status is non-zero, git commit will abort.

          The purpose of the hook is to edit the message file in
          place, and it is not suppressed by the --no-verify option. A
          non-zero exit means a failure of the hook and aborts the
          commit. It should not be used as replacement for pre-commit
          hook.

          The sample prepare-commit-msg hook that comes with Git
          removes the help message found in the commented portion of
          the commit template.

        commit-msg
          This hook is invoked by git-commit(1) and git-merge(1), and
          can be bypassed with the --no-verify option. It takes a
          single parameter, the name of the file that holds the
          proposed commit log message. Exiting with a non-zero status
          causes the command to abort.

          The hook is allowed to edit the message file in place, and
          can be used to normalize the message into some project
          standard format. It can also be used to refuse the commit
          after inspecting the message file.

          The default commit-msg hook, when enabled, detects duplicate
          Signed-off-by trailers, and aborts the commit if one is
          found.

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        post-commit
          This hook is invoked by git-commit(1). It takes no
          parameters, and is invoked after a commit is made.

          This hook is meant primarily for notification, and cannot
          affect the outcome of git commit.

        pre-rebase
          This hook is called by git-rebase(1) and can be used to
          prevent a branch from getting rebased. The hook may be
          called with one or two parameters. The first parameter is
          the upstream from which the series was forked. The second
          parameter is the branch being rebased, and is not set when
          rebasing the current branch.

        post-checkout
          This hook is invoked when a git-checkout(1) or git-switch(1)
          is run after having updated the worktree. The hook is given
          three parameters: the ref of the previous HEAD, the ref of
          the new HEAD (which may or may not have changed), and a flag
          indicating whether the checkout was a branch checkout
          (changing branches, flag=1) or a file checkout (retrieving a
          file from the index, flag=0). This hook cannot affect the
          outcome of git switch or git checkout, other than that the
          hookcqs exit status becomes the exit status of these two
          commands.

          It is also run after git-clone(1), unless the --no-checkout
          (-n) option is used. The first parameter given to the hook
          is the null-ref, the second the ref of the new HEAD and the
          flag is always 1. Likewise for git worktree add unless
          --no-checkout is used.

          This hook can be used to perform repository validity checks,
          auto-display differences from the previous HEAD if
          different, or set working dir metadata properties.

        post-merge
          This hook is invoked by git-merge(1), which happens when a
          git pull is done on a local repository. The hook takes a
          single parameter, a status flag specifying whether or not
          the merge being done was a squash merge. This hook cannot
          affect the outcome of git merge and is not executed, if the
          merge failed due to conflicts.

          This hook can be used in conjunction with a corresponding
          pre-commit hook to save and restore any form of metadata
          associated with the working tree (e.g.:
          permissions/ownership, ACLS, etc). See
          contrib/hooks/setgitperms.perl for an example of how to do
          this.

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        pre-push
          This hook is called by git-push(1) and can be used to
          prevent a push from taking place. The hook is called with
          two parameters which provide the name and location of the
          destination remote, if a named remote is not being used both
          values will be the same.

          Information about what is to be pushed is provided on the
          hookcqs standard input with lines of the form:

              <local ref> SP <local object name> SP <remote ref> SP <remote object name> LF

          For instance, if the command git push origin master:foreign
          were run the hook would receive a line like the following:

              refs/heads/master 67890 refs/heads/foreign 12345

          although the full object name would be supplied. If the
          foreign ref does not yet exist the <remote object name> will
          be the all-zeroes object name. If a ref is to be deleted,
          the <local ref> will be supplied as (delete) and the <local
          object name> will be the all-zeroes object name. If the
          local commit was specified by something other than a name
          which could be expanded (such as HEAD~, or an object name)
          it will be supplied as it was originally given.

          If this hook exits with a non-zero status, git push will
          abort without pushing anything. Information about why the
          push is rejected may be sent to the user by writing to
          standard error.

        pre-receive
          This hook is invoked by git-receive-pack(1) when it reacts
          to git push and updates reference(s) in its repository. Just
          before starting to update refs on the remote repository, the
          pre-receive hook is invoked. Its exit status determines the
          success or failure of the update.

          This hook executes once for the receive operation. It takes
          no arguments, but for each ref to be updated it receives on
          standard input a line of the format:

              <old-value> SP <new-value> SP <ref-name> LF

          where <old-value> is the old object name stored in the ref,
          <new-value> is the new object name to be stored in the ref
          and <ref-name> is the full name of the ref. When creating a
          new ref, <old-value> is the all-zeroes object name.

          If the hook exits with non-zero status, none of the refs
          will be updated. If the hook exits with zero, updating of
          individual refs can still be prevented by the update hook.

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          Both standard output and standard error output are forwarded
          to git send-pack on the other end, so you can simply echo
          messages for the user.

          The number of push options given on the command line of git
          push --push-option=... can be read from the environment
          variable GIT_PUSH_OPTION_COUNT, and the options themselves
          are found in GIT_PUSH_OPTION_0, GIT_PUSH_OPTION_1,... If it
          is negotiated to not use the push options phase, the
          environment variables will not be set. If the client selects
          to use push options, but doesncqt transmit any, the count
          variable will be set to zero, GIT_PUSH_OPTION_COUNT=0.

          See the section on "Quarantine Environment" in git-receive-
          pack(1) for some caveats.

        update
          This hook is invoked by git-receive-pack(1) when it reacts
          to git push and updates reference(s) in its repository. Just
          before updating the ref on the remote repository, the update
          hook is invoked. Its exit status determines the success or
          failure of the ref update.

          The hook executes once for each ref to be updated, and takes
          three parameters:

          +o   the name of the ref being updated,

          +o   the old object name stored in the ref,

          +o   and the new object name to be stored in the ref.

          A zero exit from the update hook allows the ref to be
          updated. Exiting with a non-zero status prevents git
          receive-pack from updating that ref.

          This hook can be used to prevent forced update on certain
          refs by making sure that the object name is a commit object
          that is a descendant of the commit object named by the old
          object name. That is, to enforce a "fast-forward only"
          policy.

          It could also be used to log the old..new status. However,
          it does not know the entire set of branches, so it would end
          up firing one e-mail per ref when used naively, though. The
          post-receive hook is more suited to that.

          In an environment that restricts the users' access only to
          git commands over the wire, this hook can be used to
          implement access control without relying on filesystem
          ownership and group membership. See git-shell(1) for how you
          might use the login shell to restrict the usercqs access to

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          only git commands.

          Both standard output and standard error output are forwarded
          to git send-pack on the other end, so you can simply echo
          messages for the user.

          The default update hook, when enabled-and with
          hooks.allowunannotated config option unset or set to false-
          prevents unannotated tags to be pushed.

        proc-receive
          This hook is invoked by git-receive-pack(1). If the server
          has set the multi-valued config variable
          receive.procReceiveRefs, and the commands sent to
          receive-pack have matching reference names, these commands
          will be executed by this hook, instead of by the internal
          execute_commands() function. This hook is responsible for
          updating the relevant references and reporting the results
          back to receive-pack.

          This hook executes once for the receive operation. It takes
          no arguments, but uses a pkt-line format protocol to
          communicate with receive-pack to read commands, push-options
          and send results. In the following example for the protocol,
          the letter S stands for receive-pack and the letter H stands
          for this hook.

              # Version and features negotiation.
              S: PKT-LINE(version=1\0push-options atomic...)
              S: flush-pkt
              H: PKT-LINE(version=1\0push-options...)
              H: flush-pkt

              # Send commands from server to the hook.
              S: PKT-LINE(<old-oid> <new-oid> <ref>)
              S: ... ...
              S: flush-pkt
              # Send push-options only if the 'push-options' feature is enabled.
              S: PKT-LINE(push-option)
              S: ... ...
              S: flush-pkt

              # Receive result from the hook.
              # OK, run this command successfully.
              H: PKT-LINE(ok <ref>)
              # NO, I reject it.
              H: PKT-LINE(ng <ref> <reason>)
              # Fall through, let 'receive-pack' to execute it.
              H: PKT-LINE(ok <ref>)
              H: PKT-LINE(option fall-through)
              # OK, but has an alternate reference.  The alternate reference name
              # and other status can be given in option directives.

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              H: PKT-LINE(ok <ref>)
              H: PKT-LINE(option refname <refname>)
              H: PKT-LINE(option old-oid <old-oid>)
              H: PKT-LINE(option new-oid <new-oid>)
              H: PKT-LINE(option forced-update)
              H: ... ...
              H: flush-pkt

          Each command for the proc-receive hook may point to a
          pseudo-reference and always has a zero-old as its old-oid,
          while the proc-receive hook may update an alternate
          reference and the alternate reference may exist already with
          a non-zero old-oid. For this case, this hook will use
          "option" directives to report extended attributes for the
          reference given by the leading "ok" directive.

          The report of the commands of this hook should have the same
          order as the input. The exit status of the proc-receive hook
          only determines the success or failure of the group of
          commands sent to it, unless atomic push is in use.

        post-receive
          This hook is invoked by git-receive-pack(1) when it reacts
          to git push and updates reference(s) in its repository. It
          executes on the remote repository once after all the refs
          have been updated.

          This hook executes once for the receive operation. It takes
          no arguments, but gets the same information as the
          pre-receive hook does on its standard input.

          This hook does not affect the outcome of git receive-pack,
          as it is called after the real work is done.

          This supersedes the post-update hook in that it gets both
          old and new values of all the refs in addition to their
          names.

          Both standard output and standard error output are forwarded
          to git send-pack on the other end, so you can simply echo
          messages for the user.

          The default post-receive hook is empty, but there is a
          sample script post-receive-email provided in the
          contrib/hooks directory in Git distribution, which
          implements sending commit emails.

          The number of push options given on the command line of git
          push --push-option=... can be read from the environment
          variable GIT_PUSH_OPTION_COUNT, and the options themselves
          are found in GIT_PUSH_OPTION_0, GIT_PUSH_OPTION_1,... If it
          is negotiated to not use the push options phase, the

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          environment variables will not be set. If the client selects
          to use push options, but doesncqt transmit any, the count
          variable will be set to zero, GIT_PUSH_OPTION_COUNT=0.

        post-update
          This hook is invoked by git-receive-pack(1) when it reacts
          to git push and updates reference(s) in its repository. It
          executes on the remote repository once after all the refs
          have been updated.

          It takes a variable number of parameters, each of which is
          the name of ref that was actually updated.

          This hook is meant primarily for notification, and cannot
          affect the outcome of git receive-pack.

          The post-update hook can tell what are the heads that were
          pushed, but it does not know what their original and updated
          values are, so it is a poor place to do log old..new. The
          post-receive hook does get both original and updated values
          of the refs. You might consider it instead if you need them.

          When enabled, the default post-update hook runs git
          update-server-info to keep the information used by dumb
          transports (e.g., HTTP) up to date. If you are publishing a
          Git repository that is accessible via HTTP, you should
          probably enable this hook.

          Both standard output and standard error output are forwarded
          to git send-pack on the other end, so you can simply echo
          messages for the user.

        reference-transaction
          This hook is invoked by any Git command that performs
          reference updates. It executes whenever a reference
          transaction is prepared, committed or aborted and may thus
          get called multiple times. The hook does not cover symbolic
          references (but that may change in the future).

          The hook takes exactly one argument, which is the current
          state the given reference transaction is in:

          +o   "prepared": All reference updates have been queued to
              the transaction and references were locked on disk.

          +o   "committed": The reference transaction was committed and
              all references now have their respective new value.

          +o   "aborted": The reference transaction was aborted, no
              changes were performed and the locks have been released.

          For each reference update that was added to the transaction,

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          the hook receives on standard input a line of the format:

              <old-value> SP <new-value> SP <ref-name> LF

          where <old-value> is the old object name passed into the
          reference transaction, <new-value> is the new object name to
          be stored in the ref and <ref-name> is the full name of the
          ref. When force updating the reference regardless of its
          current value or when the reference is to be created anew,
          <old-value> is the all-zeroes object name. To distinguish
          these cases, you can inspect the current value of <ref-name>
          via git rev-parse.

          The exit status of the hook is ignored for any state except
          for the "prepared" state. In the "prepared" state, a
          non-zero exit status will cause the transaction to be
          aborted. The hook will not be called with "aborted" state in
          that case.

        push-to-checkout
          This hook is invoked by git-receive-pack(1) when it reacts
          to git push and updates reference(s) in its repository, and
          when the push tries to update the branch that is currently
          checked out and the receive.denyCurrentBranch configuration
          variable is set to updateInstead. Such a push by default is
          refused if the working tree and the index of the remote
          repository has any difference from the currently checked out
          commit; when both the working tree and the index match the
          current commit, they are updated to match the newly pushed
          tip of the branch. This hook is to be used to override the
          default behaviour.

          The hook receives the commit with which the tip of the
          current branch is going to be updated. It can exit with a
          non-zero status to refuse the push (when it does so, it must
          not modify the index or the working tree). Or it can make
          any necessary changes to the working tree and to the index
          to bring them to the desired state when the tip of the
          current branch is updated to the new commit, and exit with a
          zero status.

          For example, the hook can simply run git read-tree -u -m
          HEAD "$1" in order to emulate git fetch that is run in the
          reverse direction with git push, as the two-tree form of git
          read-tree -u -m is essentially the same as git switch or git
          checkout that switches branches while keeping the local
          changes in the working tree that do not interfere with the
          difference between the branches.

        pre-auto-gc
          This hook is invoked by git gc --auto (see git-gc(1)). It
          takes no parameter, and exiting with non-zero status from

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          this script causes the git gc --auto to abort.

        post-rewrite
          This hook is invoked by commands that rewrite commits (git-
          commit(1) when called with --amend and git-rebase(1);
          however, full-history (re)writing tools like git-fast-
          import(1) or m[blue]git-filter-repom[][1] typically do not
          call it!). Its first argument denotes the command it was
          invoked by: currently one of amend or rebase. Further
          command-dependent arguments may be passed in the future.

          The hook receives a list of the rewritten commits on stdin,
          in the format

              <old-object-name> SP <new-object-name> [ SP <extra-info> ] LF

          The extra-info is again command-dependent. If it is empty,
          the preceding SP is also omitted. Currently, no commands
          pass any extra-info.

          The hook always runs after the automatic note copying (see
          "notes.rewrite.<command>" in git-config(1)) has happened,
          and thus has access to these notes.

          The following command-specific comments apply:

          rebase
              For the squash and fixup operation, all commits that
              were squashed are listed as being rewritten to the
              squashed commit. This means that there will be several
              lines sharing the same new-object-name.

              The commits are guaranteed to be listed in the order
              that they were processed by rebase.

        sendemail-validate
          This hook is invoked by git-send-email(1). It takes a single
          parameter, the name of the file that holds the e-mail to be
          sent. Exiting with a non-zero status causes git send-email
          to abort before sending any e-mails.

        fsmonitor-watchman
          This hook is invoked when the configuration option
          core.fsmonitor is set to .git/hooks/fsmonitor-watchman or
          .git/hooks/fsmonitor-watchmanv2 depending on the version of
          the hook to use.

          Version 1 takes two arguments, a version (1) and the time in
          elapsed nanoseconds since midnight, January 1, 1970.

          Version 2 takes two arguments, a version (2) and a token
          that is used for identifying changes since the token. For

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          watchman this would be a clock id. This version must output
          to stdout the new token followed by a NUL before the list of
          files.

          The hook should output to stdout the list of all files in
          the working directory that may have changed since the
          requested time. The logic should be inclusive so that it
          does not miss any potential changes. The paths should be
          relative to the root of the working directory and be
          separated by a single NUL.

          It is OK to include files which have not actually changed.
          All changes including newly-created and deleted files should
          be included. When files are renamed, both the old and the
          new name should be included.

          Git will limit what files it checks for changes as well as
          which directories are checked for untracked files based on
          the path names given.

          An optimized way to tell git "all files have changed" is to
          return the filename /.

          The exit status determines whether git will use the data
          from the hook to limit its search. On error, it will fall
          back to verifying all files and folders.

        p4-changelist
          This hook is invoked by git-p4 submit.

          The p4-changelist hook is executed after the changelist
          message has been edited by the user. It can be bypassed with
          the --no-verify option. It takes a single parameter, the
          name of the file that holds the proposed changelist text.
          Exiting with a non-zero status causes the command to abort.

          The hook is allowed to edit the changelist file and can be
          used to normalize the text into some project standard
          format. It can also be used to refuse the Submit after
          inspect the message file.

          Run git-p4 submit --help for details.

        p4-prepare-changelist
          This hook is invoked by git-p4 submit.

          The p4-prepare-changelist hook is executed right after
          preparing the default changelist message and before the
          editor is started. It takes one parameter, the name of the
          file that contains the changelist text. Exiting with a
          non-zero status from the script will abort the process.

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          The purpose of the hook is to edit the message file in
          place, and it is not suppressed by the --no-verify option.
          This hook is called even if --prepare-p4-only is set.

          Run git-p4 submit --help for details.

        p4-post-changelist
          This hook is invoked by git-p4 submit.

          The p4-post-changelist hook is invoked after the submit has
          successfully occurred in P4. It takes no parameters and is
          meant primarily for notification and cannot affect the
          outcome of the git p4 submit action.

          Run git-p4 submit --help for details.

        p4-pre-submit
          This hook is invoked by git-p4 submit. It takes no
          parameters and nothing from standard input. Exiting with
          non-zero status from this script prevent git-p4 submit from
          launching. It can be bypassed with the --no-verify command
          line option. Run git-p4 submit --help for details.

        post-index-change
          This hook is invoked when the index is written in
          read-cache.c do_write_locked_index.

          The first parameter passed to the hook is the indicator for
          the working directory being updated. "1" meaning working
          directory was updated or "0" when the working directory was
          not updated.

          The second parameter passed to the hook is the indicator for
          whether or not the index was updated and the skip-worktree
          bit could have changed. "1" meaning skip-worktree bits could
          have been updated and "0" meaning they were not.

          Only one parameter should be set to "1" when the hook runs.
          The hook running passing "1", "1" should not be possible.

     GIT
          Part of the git(1) suite

     NOTES
           1. git-filter-repo
              https://github.com/newren/git-filter-repo

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