perlgit(1)


NAME

   perlgit - Detailed information about git and the Perl repository

DESCRIPTION

   This document provides details on using git to develop Perl. If you are
   just interested in working on a quick patch, see perlhack first.  This
   document is intended for people who are regular contributors to Perl,
   including those with write access to the git repository.

CLONING THE REPOSITORY

   All of Perl's source code is kept centrally in a Git repository at
   perl5.git.perl.org.

   You can make a read-only clone of the repository by running:

     % git clone git://perl5.git.perl.org/perl.git perl

   This uses the git protocol (port 9418).

   If you cannot use the git protocol for firewall reasons, you can also
   clone via http, though this is much slower:

     % git clone http://perl5.git.perl.org/perl.git perl

WORKING WITH THE REPOSITORY

   Once you have changed into the repository directory, you can inspect
   it. After a clone the repository will contain a single local branch,
   which will be the current branch as well, as indicated by the asterisk.

     % git branch
     * blead

   Using the -a switch to "branch" will also show the remote tracking
   branches in the repository:

     % git branch -a
     * blead
       origin/HEAD
       origin/blead
     ...

   The branches that begin with "origin" correspond to the "git remote"
   that you cloned from (which is named "origin"). Each branch on the
   remote will be exactly tracked by these branches. You should NEVER do
   work on these remote tracking branches. You only ever do work in a
   local branch. Local branches can be configured to automerge (on pull)
   from a designated remote tracking branch. This is the case with the
   default branch "blead" which will be configured to merge from the
   remote tracking branch "origin/blead".

   You can see recent commits:

     % git log

   And pull new changes from the repository, and update your local
   repository (must be clean first)

     % git pull

   Assuming we are on the branch "blead" immediately after a pull, this
   command would be more or less equivalent to:

     % git fetch
     % git merge origin/blead

   In fact if you want to update your local repository without touching
   your working directory you do:

     % git fetch

   And if you want to update your remote-tracking branches for all defined
   remotes simultaneously you can do

     % git remote update

   Neither of these last two commands will update your working directory,
   however both will update the remote-tracking branches in your
   repository.

   To make a local branch of a remote branch:

     % git checkout -b maint-5.10 origin/maint-5.10

   To switch back to blead:

     % git checkout blead

   Finding out your status
   The most common git command you will use will probably be

     % git status

   This command will produce as output a description of the current state
   of the repository, including modified files and unignored untracked
   files, and in addition it will show things like what files have been
   staged for the next commit, and usually some useful information about
   how to change things. For instance the following:

    % git status
    On branch blead
    Your branch is ahead of 'origin/blead' by 1 commit.

    Changes to be committed:
      (use "git reset HEAD <file>..." to unstage)

          modified:   pod/perlgit.pod

    Changes not staged for commit:
      (use "git add <file>..." to update what will be committed)
      (use "git checkout -- <file>..." to discard changes in working
                                                                 directory)

          modified:   pod/perlgit.pod

    Untracked files:
      (use "git add <file>..." to include in what will be committed)

          deliberate.untracked

   This shows that there were changes to this document staged for commit,
   and that there were further changes in the working directory not yet
   staged. It also shows that there was an untracked file in the working
   directory, and as you can see shows how to change all of this. It also
   shows that there is one commit on the working branch "blead" which has
   not been pushed to the "origin" remote yet. NOTE: This output is also
   what you see as a template if you do not provide a message to "git
   commit".

   Patch workflow
   First, please read perlhack for details on hacking the Perl core.  That
   document covers many details on how to create a good patch.

   If you already have a Perl repository, you should ensure that you're on
   the blead branch, and your repository is up to date:

     % git checkout blead
     % git pull

   It's preferable to patch against the latest blead version, since this
   is where new development occurs for all changes other than critical bug
   fixes. Critical bug fix patches should be made against the relevant
   maint branches, or should be submitted with a note indicating all the
   branches where the fix should be applied.

   Now that we have everything up to date, we need to create a temporary
   new branch for these changes and switch into it:

     % git checkout -b orange

   which is the short form of

     % git branch orange
     % git checkout orange

   Creating a topic branch makes it easier for the maintainers to rebase
   or merge back into the master blead for a more linear history. If you
   don't work on a topic branch the maintainer has to manually cherry pick
   your changes onto blead before they can be applied.

   That'll get you scolded on perl5-porters, so don't do that. Be Awesome.

   Then make your changes. For example, if Leon Brocard changes his name
   to Orange Brocard, we should change his name in the AUTHORS file:

     % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS

   You can see what files are changed:

     % git status
     On branch orange
     Changes to be committed:
       (use "git reset HEAD <file>..." to unstage)

        modified:   AUTHORS

   And you can see the changes:

    % git diff
    diff --git a/AUTHORS b/AUTHORS
    index 293dd70..722c93e 100644
    --- a/AUTHORS
    +++ b/AUTHORS
    @@ -541,7 +541,7 @@    Lars Hecking              <lhecking@nmrc.ucc.ie>
     Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
     Leif Huhn                      <leif@hale.dkstat.com>
     Len Johnson                    <lenjay@ibm.net>
    -Leon Brocard                   <acme@astray.com>
    +Orange Brocard                 <acme@astray.com>
     Les Peters                     <lpeters@aol.net>
     Lesley Binks                   <lesley.binks@gmail.com>
     Lincoln D. Stein               <lstein@cshl.org>

   Now commit your change locally:

    % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
    Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
     1 files changed, 1 insertions(+), 1 deletions(-)

   The "-a" option is used to include all files that git tracks that you
   have changed. If at this time, you only want to commit some of the
   files you have worked on, you can omit the "-a" and use the command
   "gitaddFILE..." before doing the commit. "gitadd--interactive"
   allows you to even just commit portions of files instead of all the
   changes in them.

   The "-m" option is used to specify the commit message. If you omit it,
   git will open a text editor for you to compose the message
   interactively. This is useful when the changes are more complex than
   the sample given here, and, depending on the editor, to know that the
   first line of the commit message doesn't exceed the 50 character legal
   maximum.

   Once you've finished writing your commit message and exited your
   editor, git will write your change to disk and tell you something like
   this:

    Created commit daf8e63: explain git status and stuff about remotes
     1 files changed, 83 insertions(+), 3 deletions(-)

   If you re-run "git status", you should see something like this:

    % git status
    On branch orange
    Untracked files:
      (use "git add <file>..." to include in what will be committed)

          deliberate.untracked

    nothing added to commit but untracked files present (use "git add" to
                                                                     track)

   When in doubt, before you do anything else, check your status and read
   it carefully, many questions are answered directly by the git status
   output.

   You can examine your last commit with:

     % git show HEAD

   and if you are not happy with either the description or the patch
   itself you can fix it up by editing the files once more and then issue:

     % git commit -a --amend

   Now you should create a patch file for all your local changes:

     % git format-patch -M blead..
     0001-Rename-Leon-Brocard-to-Orange-Brocard.patch

   Or for a lot of changes, e.g. from a topic branch:

     % git format-patch --stdout -M blead.. > topic-branch-changes.patch

   You should now send an email to perlbug@perl.org
   <mailto:perlbug@perl.org> with a description of your changes, and
   include this patch file as an attachment. In addition to being tracked
   by RT, mail to perlbug will automatically be forwarded to perl5-porters
   (with manual moderation, so please be patient). You should only send
   patches to perl5-porters@perl.org <mailto:perl5-porters@perl.org>
   directly if the patch is not ready to be applied, but intended for
   discussion.

   Please do not use git-send-email(1) to send your patch. See Sending
   patch emails for more information.

   If you want to delete your temporary branch, you may do so with:

    % git checkout blead
    % git branch -d orange
    error: The branch 'orange' is not an ancestor of your current HEAD.
    If you are sure you want to delete it, run 'git branch -D orange'.
    % git branch -D orange
    Deleted branch orange.

   Committing your changes
   Assuming that you'd like to commit all the changes you've made as a
   single atomic unit, run this command:

     % git commit -a

   (That "-a" tells git to add every file you've changed to this commit.
   New files aren't automatically added to your commit when you use
   "commit -a" If you want to add files or to commit some, but not all of
   your changes, have a look at the documentation for "git add".)

   Git will start up your favorite text editor, so that you can craft a
   commit message for your change. See "Commit message" in perlhack for
   more information about what makes a good commit message.

   Once you've finished writing your commit message and exited your
   editor, git will write your change to disk and tell you something like
   this:

    Created commit daf8e63: explain git status and stuff about remotes
     1 files changed, 83 insertions(+), 3 deletions(-)

   If you re-run "git status", you should see something like this:

    % git status
    On branch blead
    Your branch is ahead of 'origin/blead' by 2 commits.
      (use "git push" to publish your local commits)
    Untracked files:
      (use "git add <file>..." to include in what will be committed)

          deliberate.untracked

    nothing added to commit but untracked files present (use "git add" to
                                                                     track)

   When in doubt, before you do anything else, check your status and read
   it carefully, many questions are answered directly by the git status
   output.

   Sending patch emails
   After you've generated your patch you should send it to
   perlbug@perl.org <mailto:perlbug@perl.org> (as discussed in the
   previous section) with a normal mail client as an attachment, along
   with a description of the patch.

   You must not use git-send-email(1) to send patches generated with
   git-format-patch(1). The RT ticketing system living behind
   perlbug@perl.org <mailto:perlbug@perl.org> does not respect the inline
   contents of E-Mails, sending an inline patch to RT guarantees that your
   patch will be destroyed.

   Someone may download your patch from RT, which will result in the
   subject (the first line of the commit message) being omitted.  See RT
   #74192 <https://rt.perl.org/Ticket/Display.html?id=74192> and commit
   a4583001 <http://perl5.git.perl.org/perl.git/commitdiff/a4583001> for
   an example. Alternatively someone may apply your patch from RT after it
   arrived in their mailbox, by which time RT will have modified the
   inline content of the message.  See RT #74532
   <https://rt.perl.org/Ticket/Display.html?id=74532> and commit f9bcfeac
   <http://perl5.git.perl.org/perl.git/commitdiff/f9bcfeac> for a bad
   example of this failure mode.

   A note on derived files
   Be aware that many files in the distribution are derivative--avoid
   patching them, because git won't see the changes to them, and the build
   process will overwrite them. Patch the originals instead. Most
   utilities (like perldoc) are in this category, i.e. patch
   utils/perldoc.PL rather than utils/perldoc. Similarly, don't create
   patches for files under $src_root/ext from their copies found in
   $install_root/lib. If you are unsure about the proper location of a
   file that may have gotten copied while building the source
   distribution, consult the MANIFEST.

   Cleaning a working directory
   The command "git clean" can with varying arguments be used as a
   replacement for "make clean".

   To reset your working directory to a pristine condition you can do:

     % git clean -dxf

   However, be aware this will delete ALL untracked content. You can use

     % git clean -Xf

   to remove all ignored untracked files, such as build and test
   byproduct, but leave any manually created files alone.

   If you only want to cancel some uncommitted edits, you can use "git
   checkout" and give it a list of files to be reverted, or "git checkout
   -f" to revert them all.

   If you want to cancel one or several commits, you can use "git reset".

   Bisecting
   "git" provides a built-in way to determine which commit should be
   blamed for introducing a given bug. "git bisect" performs a binary
   search of history to locate the first failing commit. It is fast,
   powerful and flexible, but requires some setup and to automate the
   process an auxiliary shell script is needed.

   The core provides a wrapper program, Porting/bisect.pl, which attempts
   to simplify as much as possible, making bisecting as simple as running
   a Perl one-liner. For example, if you want to know when this became an
   error:

       perl -e 'my $a := 2'

   you simply run this:

       .../Porting/bisect.pl -e 'my $a := 2;'

   Using Porting/bisect.pl, with one command (and no other files) it's
   easy to find out

   *   Which commit caused this example code to break?

   *   Which commit caused this example code to start working?

   *   Which commit added the first file to match this regex?

   *   Which commit removed the last file to match this regex?

   usually without needing to know which versions of perl to use as start
   and end revisions, as Porting/bisect.pl automatically searches to find
   the earliest stable version for which the test case passes. Run
   "Porting/bisect.pl --help" for the full documentation, including how to
   set the "Configure" and build time options.

   If you require more flexibility than Porting/bisect.pl has to offer,
   you'll need to run "git bisect" yourself. It's most useful to use "git
   bisect run" to automate the building and testing of perl revisions. For
   this you'll need a shell script for "git" to call to test a particular
   revision. An example script is Porting/bisect-example.sh, which you
   should copy outside of the repository, as the bisect process will reset
   the state to a clean checkout as it runs. The instructions below assume
   that you copied it as ~/run and then edited it as appropriate.

   You first enter in bisect mode with:

     % git bisect start

   For example, if the bug is present on "HEAD" but wasn't in 5.10.0,
   "git" will learn about this when you enter:

     % git bisect bad
     % git bisect good perl-5.10.0
     Bisecting: 853 revisions left to test after this

   This results in checking out the median commit between "HEAD" and
   "perl-5.10.0". You can then run the bisecting process with:

     % git bisect run ~/run

   When the first bad commit is isolated, "git bisect" will tell you so:

     ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
     commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
     Author: Dave Mitchell <davem@fdisolutions.com>
     Date:   Sat Feb 9 14:56:23 2008 +0000

         [perl #49472] Attributes + Unknown Error
         ...

     bisect run success

   You can peek into the bisecting process with "git bisect log" and "git
   bisect visualize". "git bisect reset" will get you out of bisect mode.

   Please note that the first "good" state must be an ancestor of the
   first "bad" state. If you want to search for the commit that solved
   some bug, you have to negate your test case (i.e. exit with 1 if OK and
   0 if not) and still mark the lower bound as "good" and the upper as
   "bad". The "first bad commit" has then to be understood as the "first
   commit where the bug is solved".

   "git help bisect" has much more information on how you can tweak your
   binary searches.

   Topic branches and rewriting history
   Individual committers should create topic branches under
   yourname/some_descriptive_name:

     % branch="$yourname/$some_descriptive_name"
     % git checkout -b $branch
     ... do local edits, commits etc ...
     % git push origin -u $branch

   Should you be stuck with an ancient version of git (prior to 1.7), then
   "git push" will not have the "-u" switch, and you have to replace the
   last step with the following sequence:

     % git push origin $branch:refs/heads/$branch
     % git config branch.$branch.remote origin
     % git config branch.$branch.merge refs/heads/$branch

   If you want to make changes to someone else's topic branch, you should
   check with its creator before making any change to it.

   You might sometimes find that the original author has edited the
   branch's history. There are lots of good reasons for this. Sometimes,
   an author might simply be rebasing the branch onto a newer source
   point.  Sometimes, an author might have found an error in an early
   commit which they wanted to fix before merging the branch to blead.

   Currently the master repository is configured to forbid non-fast-
   forward merges. This means that the branches within can not be rebased
   and pushed as a single step.

   The only way you will ever be allowed to rebase or modify the history
   of a pushed branch is to delete it and push it as a new branch under
   the same name. Please think carefully about doing this. It may be
   better to sequentially rename your branches so that it is easier for
   others working with you to cherry-pick their local changes onto the new
   version. (XXX: needs explanation).

   If you want to rebase a personal topic branch, you will have to delete
   your existing topic branch and push as a new version of it. You can do
   this via the following formula (see the explanation about "refspec"'s
   in the git push documentation for details) after you have rebased your
   branch:

     # first rebase
     % git checkout $user/$topic
     % git fetch
     % git rebase origin/blead

     # then "delete-and-push"
     % git push origin :$user/$topic
     % git push origin $user/$topic

   NOTE: it is forbidden at the repository level to delete any of the
   "primary" branches. That is any branch matching
   "m!^(blead|maint|perl)!". Any attempt to do so will result in git
   producing an error like this:

     % git push origin :blead
     *** It is forbidden to delete blead/maint branches in this repository
     error: hooks/update exited with error code 1
     error: hook declined to update refs/heads/blead
     To ssh://perl5.git.perl.org/perl
      ! [remote rejected] blead (hook declined)
      error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'

   As a matter of policy we do not edit the history of the blead and
   maint-* branches. If a typo (or worse) sneaks into a commit to blead or
   maint-*, we'll fix it in another commit. The only types of updates
   allowed on these branches are "fast-forwards", where all history is
   preserved.

   Annotated tags in the canonical perl.git repository will never be
   deleted or modified. Think long and hard about whether you want to push
   a local tag to perl.git before doing so. (Pushing simple tags is not
   allowed.)

   Grafts
   The perl history contains one mistake which was not caught in the
   conversion: a merge was recorded in the history between blead and
   maint-5.10 where no merge actually occurred. Due to the nature of git,
   this is now impossible to fix in the public repository. You can remove
   this mis-merge locally by adding the following line to your
   ".git/info/grafts" file:

    296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930

   It is particularly important to have this graft line if any bisecting
   is done in the area of the "merge" in question.

WRITE ACCESS TO THE GIT REPOSITORY

   Once you have write access, you will need to modify the URL for the
   origin remote to enable pushing. Edit .git/config with the
   git-config(1) command:

     % git config remote.origin.url ssh://perl5.git.perl.org/perl.git

   You can also set up your user name and e-mail address. Most people do
   this once globally in their ~/.gitconfig by doing something like:

     % git config --global user.name "var Arnfjr Bjarmason"
     % git config --global user.email avarab@gmail.com

   However, if you'd like to override that just for perl, execute
   something like the following in perl:

     % git config user.email avar@cpan.org

   It is also possible to keep "origin" as a git remote, and add a new
   remote for ssh access:

     % git remote add camel perl5.git.perl.org:/perl.git

   This allows you to update your local repository by pulling from
   "origin", which is faster and doesn't require you to authenticate, and
   to push your changes back with the "camel" remote:

     % git fetch camel
     % git push camel

   The "fetch" command just updates the "camel" refs, as the objects
   themselves should have been fetched when pulling from "origin".

   Accepting a patch
   If you have received a patch file generated using the above section,
   you should try out the patch.

   First we need to create a temporary new branch for these changes and
   switch into it:

    % git checkout -b experimental

   Patches that were formatted by "git format-patch" are applied with "git
   am":

    % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
    Applying Rename Leon Brocard to Orange Brocard

   Note that some UNIX mail systems can mess with text attachments
   containing 'From '. This will fix them up:

    % perl -pi -e's/^>From /From /' \
                           0001-Rename-Leon-Brocard-to-Orange-Brocard.patch

   If just a raw diff is provided, it is also possible use this two-step
   process:

    % git apply bugfix.diff
    % git commit -a -m "Some fixing" \
                               --author="That Guy <that.guy@internets.com>"

   Now we can inspect the change:

    % git show HEAD
    commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
    Author: Leon Brocard <acme@astray.com>
    Date:   Fri Dec 19 17:02:59 2008 +0000

      Rename Leon Brocard to Orange Brocard

    diff --git a/AUTHORS b/AUTHORS
    index 293dd70..722c93e 100644
    --- a/AUTHORS
    +++ b/AUTHORS
    @@ -541,7 +541,7 @@ Lars Hecking                 <lhecking@nmrc.ucc.ie>
     Laszlo Molnar                  <laszlo.molnar@eth.ericsson.se>
     Leif Huhn                      <leif@hale.dkstat.com>
     Len Johnson                    <lenjay@ibm.net>
    -Leon Brocard                   <acme@astray.com>
    +Orange Brocard                 <acme@astray.com>
     Les Peters                     <lpeters@aol.net>
     Lesley Binks                   <lesley.binks@gmail.com>
     Lincoln D. Stein               <lstein@cshl.org>

   If you are a committer to Perl and you think the patch is good, you can
   then merge it into blead then push it out to the main repository:

     % git checkout blead
     % git merge experimental
     % git push origin blead

   If you want to delete your temporary branch, you may do so with:

    % git checkout blead
    % git branch -d experimental
    error: The branch 'experimental' is not an ancestor of your current
    HEAD.  If you are sure you want to delete it, run 'git branch -D
    experimental'.
    % git branch -D experimental
    Deleted branch experimental.

   Committing to blead
   The 'blead' branch will become the next production release of Perl.

   Before pushing any local change to blead, it's incredibly important
   that you do a few things, lest other committers come after you with
   pitchforks and torches:

   *   Make sure you have a good commit message. See "Commit message" in
       perlhack for details.

   *   Run the test suite. You might not think that one typo fix would
       break a test file. You'd be wrong. Here's an example of where not
       running the suite caused problems. A patch was submitted that added
       a couple of tests to an existing .t. It couldn't possibly affect
       anything else, so no need to test beyond the single affected .t,
       right?  But, the submitter's email address had changed since the
       last of their submissions, and this caused other tests to fail.
       Running the test target given in the next item would have caught
       this problem.

   *   If you don't run the full test suite, at least "make test_porting".
       This will run basic sanity checks. To see which sanity checks, have
       a look in t/porting.

   *   If you make any changes that affect miniperl or core routines that
       have different code paths for miniperl, be sure to run "make
       minitest".  This will catch problems that even the full test suite
       will not catch because it runs a subset of tests under miniperl
       rather than perl.

   On merging and rebasing
   Simple, one-off commits pushed to the 'blead' branch should be simple
   commits that apply cleanly.  In other words, you should make sure your
   work is committed against the current position of blead, so that you
   can push back to the master repository without merging.

   Sometimes, blead will move while you're building or testing your
   changes.  When this happens, your push will be rejected with a message
   like this:

    To ssh://perl5.git.perl.org/perl.git
     ! [rejected]        blead -> blead (non-fast-forward)
    error: failed to push some refs to 'ssh://perl5.git.perl.org/perl.git'
    To prevent you from losing history, non-fast-forward updates were
    rejected Merge the remote changes (e.g. 'git pull') before pushing
    again.  See the 'Note about fast-forwards' section of 'git push --help'
    for details.

   When this happens, you can just rebase your work against the new
   position of blead, like this (assuming your remote for the master
   repository is "p5p"):

     % git fetch p5p
     % git rebase p5p/blead

   You will see your commits being re-applied, and you will then be able
   to push safely.  More information about rebasing can be found in the
   documentation for the git-rebase(1) command.

   For larger sets of commits that only make sense together, or that would
   benefit from a summary of the set's purpose, you should use a merge
   commit.  You should perform your work on a topic branch, which you
   should regularly rebase against blead to ensure that your code is not
   broken by blead moving.  When you have finished your work, please
   perform a final rebase and test.  Linear history is something that gets
   lost with every commit on blead, but a final rebase makes the history
   linear again, making it easier for future maintainers to see what has
   happened.  Rebase as follows (assuming your work was on the branch
   "committer/somework"):

     % git checkout committer/somework
     % git rebase blead

   Then you can merge it into master like this:

     % git checkout blead
     % git merge --no-ff --no-commit committer/somework
     % git commit -a

   The switches above deserve explanation.  "--no-ff" indicates that even
   if all your work can be applied linearly against blead, a merge commit
   should still be prepared.  This ensures that all your work will be
   shown as a side branch, with all its commits merged into the mainstream
   blead by the merge commit.

   "--no-commit" means that the merge commit will be prepared but not
   committed.  The commit is then actually performed when you run the next
   command, which will bring up your editor to describe the commit.
   Without "--no-commit", the commit would be made with nearly no useful
   message, which would greatly diminish the value of the merge commit as
   a placeholder for the work's description.

   When describing the merge commit, explain the purpose of the branch,
   and keep in mind that this description will probably be used by the
   eventual release engineer when reviewing the next perldelta document.

   Committing to maintenance versions
   Maintenance versions should only be altered to add critical bug fixes,
   see perlpolicy.

   To commit to a maintenance version of perl, you need to create a local
   tracking branch:

     % git checkout --track -b maint-5.005 origin/maint-5.005

   This creates a local branch named "maint-5.005", which tracks the
   remote branch "origin/maint-5.005". Then you can pull, commit, merge
   and push as before.

   You can also cherry-pick commits from blead and another branch, by
   using the "git cherry-pick" command. It is recommended to use the -x
   option to "git cherry-pick" in order to record the SHA1 of the original
   commit in the new commit message.

   Before pushing any change to a maint version, make sure you've
   satisfied the steps in "Committing to blead" above.

   Merging from a branch via GitHub
   While we don't encourage the submission of patches via GitHub, that
   will still happen. Here is a guide to merging patches from a GitHub
   repository.

     % git remote add avar git://github.com/avar/perl.git
     % git fetch avar

   Now you can see the differences between the branch and blead:

     % git diff avar/orange

   And you can see the commits:

     % git log avar/orange

   If you approve of a specific commit, you can cherry pick it:

     % git cherry-pick 0c24b290ae02b2ab3304f51d5e11e85eb3659eae

   Or you could just merge the whole branch if you like it all:

     % git merge avar/orange

   And then push back to the repository:

     % git push origin blead

   Using a smoke-me branch to test changes
   Sometimes a change affects code paths which you cannot test on the OSes
   which are directly available to you and it would be wise to have users
   on other OSes test the change before you commit it to blead.

   Fortunately, there is a way to get your change smoke-tested on various
   OSes: push it to a "smoke-me" branch and wait for certain automated
   smoke-testers to report the results from their OSes.

   The procedure for doing this is roughly as follows (using the example
   of of tonyc's smoke-me branch called win32stat):

   First, make a local branch and switch to it:

     % git checkout -b win32stat

   Make some changes, build perl and test your changes, then commit them
   to your local branch. Then push your local branch to a remote smoke-me
   branch:

     % git push origin win32stat:smoke-me/tonyc/win32stat

   Now you can switch back to blead locally:

     % git checkout blead

   and continue working on other things while you wait a day or two,
   keeping an eye on the results reported for your smoke-me branch at
   <http://perl.develop-help.com/?b=smoke-me/tonyc/win32state>.

   If all is well then update your blead branch:

     % git pull

   then checkout your smoke-me branch once more and rebase it on blead:

     % git rebase blead win32stat

   Now switch back to blead and merge your smoke-me branch into it:

     % git checkout blead
     % git merge win32stat

   As described earlier, if there are many changes on your smoke-me branch
   then you should prepare a merge commit in which to give an overview of
   those changes by using the following command instead of the last
   command above:

     % git merge win32stat --no-ff --no-commit

   You should now build perl and test your (merged) changes one last time
   (ideally run the whole test suite, but failing that at least run the
   t/porting/*.t tests) before pushing your changes as usual:

     % git push origin blead

   Finally, you should then delete the remote smoke-me branch:

     % git push origin :smoke-me/tonyc/win32stat

   (which is likely to produce a warning like this, which can be ignored:

    remote: fatal: ambiguous argument
                                     'refs/heads/smoke-me/tonyc/win32stat':
    unknown revision or path not in the working tree.
    remote: Use '--' to separate paths from revisions

   ) and then delete your local branch:

     % git branch -d win32stat

   A note on camel and dromedary
   The committers have SSH access to the two servers that serve
   "perl5.git.perl.org". One is "perl5.git.perl.org" itself (camel), which
   is the 'master' repository. The second one is
   "users.perl5.git.perl.org" (dromedary), which can be used for general
   testing and development. Dromedary syncs the git tree from camel every
   few minutes, you should not push there. Both machines also have a full
   CPAN mirror in /srv/CPAN, please use this. To share files with the
   general public, dromedary serves your ~/public_html/ as
   "http://users.perl5.git.perl.org/~yourlogin/"

   These hosts have fairly strict firewalls to the outside. Outgoing, only
   rsync, ssh and git are allowed. For http and ftp, you can use
   http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
   attacks and blocks IP addresses with suspicious activity. This
   sometimes (but very rarely) has false positives and you might get
   blocked. The quickest way to get unblocked is to notify the admins.

   These two boxes are owned, hosted, and operated by booking.com. You can
   reach the sysadmins in #p5p on irc.perl.org or via mail to
   perl5-porters@perl.org <mailto:perl5-porters@perl.org>.





Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


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Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.