Real progress after having found the original source

2022-09-23 09:10:02 +01:00 · 2022-09-23 09:10:02 +01:00 · 49b806f8c0
commit 49b806f8c0
parent 5ccfcc4c5a
13 changed files with 964 additions and 19 deletions
--- a/.gitignore
+++ b/.gitignore
@ -2,3 +2,4 @@ simpleRepo
 largeFileRepo
 devTeamDemo
 GitDeepDive.html
+/GitDeepDive.html~
--- a/GitDeepDive.org
+++ b/GitDeepDive.org
@ -9,8 +9,8 @@

 #+OPTIONS: ':nil *:t -:t ::t <:t \n:nil ^:{} author:t c:nil creator:nil
 #+OPTIONS: d:nil date:t e:t email:t f:t inline:t num:nil p:nil pri:nil
-#+OPTIONS: stat:nil tags:nil tasks:t tex:t timestamp:nil toc:t todo:nil |:t
-#+DESCRIPTION: <The presentation description>
+#+OPTIONS: stat:nil tags:nil tasks:t tex:t timestamp:nil toc:1 todo:nil |:t
+#+DESCRIPTION: A journey into the depths of git
 #+LANGUAGE: en

 # <Where the reveal.js project (https://github.com/hakimel/reveal.js.git) is cloned/copied to>
@ -25,49 +25,905 @@
 #+REVEAL_HLEVEL: 1

 # <Copy this file to where the generated HTML will be>
-#+REVEAL_EXTRA_CSS: ./e-reveal.css
-#+REVEAL_EXTRA_CSS: ./gridding.css
+#+REVEAL_EXTRA_CSS: ./styles/e-reveal.css
+#+REVEAL_EXTRA_CSS: ./styles/gridding.css

 # <Copy this file to where the generated HTML will be>
-#+REVEAL_DEFAULT_SLIDE_BACKGROUND: ./bCardBackground.png
-#+REVEAL_TITLE_SLIDE_BACKGROUND: ./bCardBackground.png
-#+REVEAL_TOC_SLIDE_BACKGROUND: ./bCardBackground.png
+#+REVEAL_DEFAULT_SLIDE_BACKGROUND: ./images/bCardBackground.png
+#+REVEAL_TITLE_SLIDE_BACKGROUND: ./images/bCardBackground.png
+#+REVEAL_TOC_SLIDE_BACKGROUND: ./images/bCardBackground.png

 #+REVEAL_DEFAULT_SLIDE_SIZE: 100%
 #+REVEAL_TITLE_SLIDE_SIZE: 100%
 #+REVEAL_TOC_SLIDE_SIZE: 100%

+* Synopsis                                                         :noexport:
+
+  *Git Deep Dive*
+
+  So.
+
+  You've cloned.
+
+  You've pulled, and you've pushed.
+
+  You've branched, merged and resolved conflicts.
+
+  You may even have fetched and pruned.
+
+  You're empowered to use git as a developer, and as a team lead.
+
+  But...
+
+  Have you ever peaked under the bonnet?
+
+  What makes up a commit? What exactly is meant when we say git stores
+  changes as snapshots? Why is git sometimes called a
+  "content-addressable filesystem"? Why does that matter? What's the
+  difference between "porcelain" and "plumbing"?
+
+  This "git Deep Dive" will start off revising what developers do on a
+  normal day-to-day basis, but will quickly slip under the surface to
+  explore the different layers of a git repository, and show you the
+  tools to explore the shallows, the continental shelves, and the deep
+  trenches that hide beneath the surface of the standard developer
+  tooling.
+
+  As you emerge from this technology meet-up, awed and blinking in the
+  summer sun, you'll come away knowing some small nuggets of how to
+  solve some of the more interesting problems that you might come
+  across, but also knowing what's out there to help with that one
+  problem that will make you the git guru of your team.
+
 * Introduction
 ** Introduction
-   Assumes basic knowledge: =clone=, =add=, =commit=, =merge=, =pull=,
-   =push=
+   Assumes basic knowledge: =clone=, =add=, =commit=, =merge=, =pull=, =push=

-   Assumes comfort with the command line: =git= on Linux; =git bash=,
-   =git cmd= on Windows
+   Assumes comfort with the command line: =git= on Linux; =git bash=, =git cmd= on Windows

   - Paddling :: config, fetch-and-merge, merge approaches
-   - Snorkling and Scuba diving :: refs, =HEAD=, annotated tags,
-     submodules, =blame=, signing and verifying commits
+   - Snorkling and Scuba diving :: refs, =HEAD=, annotated tags, submodules, =blame=, signing and verifying commits
   - Submarining :: the structure of a commit, "Content Addressable Filesystem", git objects
-   - Unmanned submersibles :: the reflog, =fsck= and =gc=, finding and
-     dealing with specific git objects
-
+   - Unmanned submersibles :: the reflog, =fsck= and =gc=, finding and dealing with specific git objects
 ** About Éibhear Ó hAnluain
   - Solutions Architect
     + eibhear.geo@gmail.com
   - Software engineer since 1994
-   - Using revision control since 1994: subversion, git, IBM/Rational/Atria ClearCase, RCS, VSS, CVS, Serena SCM, Serena PVCS, SCCS
+   - Using revision control since 1994: _subversion_, _git_,
+     _IBM/Rational/Atria ClearCase_, _RCS_, _VSS_, _CVS_, _Serena
+     SCM_, _Serena PVCS_, _SCCS_
   - Introduced revision control in multiple environments
   - Multiple revision-control migrations
     + RCS -> subversion
     + VSS -> subversion
     + CVS -> git
 * The Coast
-  #+CAPTION: [[https://commons.wikimedia.org/wiki/File:Grotta_azzurra.jpg][Frédéric de Goldschmidt www.frederic.net]], [[https://creativecommons.org/licenses/by/3.0][CC BY 3.0]], via Wikimedia Commons
-  file:images/Grotta_azzurra.jpg
+  #+CAPTION: By Frédéric de Goldschmidt www.frederic.net - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=3972438
+  file:./images/Grotta_azzurra.jpg
  
+** Configuration
+   - Precedence: local (default), global, system, defaulted.
+     #+BEGIN_SRC  shell
+       git config --local --list
+       git config --global --list
+       git config --system --list
+       git config [--system|--global|--local] <key> <value>
+       git config -e
+     #+END_SRC
+** =fetch= and =merge=, not =pull=
+   - "=git pull= is just =git fetch= and then =git merge="
+   - When should you use =git pull=? When...
+     1. ... there are no local changes to be committed or pushed; and
+     2. you know the changes =pull= will make.
+   - Why?: =pull= doesn't stop to let you review the merged-in
+     changes in case it didn't go well.
+   - Suggestions:
+     + =git fetch --prune= followed by =git diff= followed by =git merge=
+     + =git pull --prune --no-commit= followed by =git commit=
+       * Allows review before commit, but doesn't apply if merge is =fast-forward=
+** =fetch= and =merge=, not =pull=
+   Other suggestions
+   - ~--prune~ :: Indicates the branches that have been removed from
+     the remote, suggesing to you to remove the local branches
+   - ~git branch -va~ :: Allows you to get a full view of the local
+     and remote branches
+** Merging approaches
+   Merging, merging strategies
+   - fast-forward :: where the tip commit of the target branch is a
+     direct ancestor of the tip commit of the source branch. Merge is
+     to re-locate the target branch label; no changes to files.
+   - Merge :: to apply the changes done on the source branch onto the
+     target branch
+
+     _Strategies_
+     + resolve
+     + recursive
+     + octopus
+     + ours
+     + subtree
+   - rebase :: to replay the changes made onto one commit onto
+     another.
+** Merging approaches: fast-forward
+   #+REVEAL_HTML: <div class="gridded_frame_with_columns">
+
+   #+REVEAL_HTML: <div class="one_of_2_columns">
+   #+ATTR_HTML: :width 70%
+   file:./images/fast-forward-initial-state.png
+   #+REVEAL_HTML: </div>
+
+   #+REVEAL_HTML: <div class="one_of_2_columns">
+   #+ATTR_REVEAL: :frag t
+   #+ATTR_HTML: :width 85%
+   file:./images/fast-forward-completed-state.png
+   #+REVEAL_HTML: </div>
+
+   #+REVEAL_HTML: </div>
+** Merging approaches: merging strategies
+   #+REVEAL_HTML: <div class="gridded_frame_with_columns">
+
+   #+REVEAL_HTML: <div class="one_of_2_columns">
+   Git automatically decides which strategy to use, but the user can
+   also specify:
+   - =recursive=: The default. For merging one branch into another,
+     seeking to ensure previous merges are handled properly.
+   - =resolve=: For merging one branch into another. Safe and fast.
+   - =octopus=: For merging 3 or more branches.
+   - =ours=: For dealing with old branches; preserves the state of the
+     target branch
+   - =subtree=: For merging trees that are at different levels.
+   #+REVEAL_HTML: </div>
+
+   #+REVEAL_HTML: <div class="one_of_2_columns">
+   #+ATTR_HTML: :width 70%
+   file:./images/two-branch-completed-state.png
+   #+REVEAL_HTML: </div>
+
+   #+REVEAL_HTML: </div>
+** Merging approaches: Rebase
+*** Rebase                                                    :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_env: block
+    :BEAMER_col: 0.55
+    :END:
+    file:./fast-forward-completed-state.png
+*** Rebase                                                            :BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.25
+    :END:
+** Merging approaches: Rebase
+*** Rebase                                                    :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_env: block
+    :BEAMER_col: 0.55
+    :END:
+    file:./fast-forward-completed-state.png
+*** Rebase                                                            :BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.25
+    :END:
+    file:./rebase-completed-state.png
+** Merging appraoches: Decision tree
+*** Fast-forward/merge/rebase decision tree                           :BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 1.0
+    :END:
+    file:./merge-decision-tree-chart.png
 * The Shallows
+** 
+*** A little deeper                                           :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.9
+    :BEAMER_env: block
+    :END:
+     file:./Naufragio_por_Gustavo_Gerdel.jpg

+#+latex: {\tiny
+     By Ggerdel - Foto de: Gustavo Gerdel (BAB Buceo) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
+#+latex: }
+** Refs
+*** Refs
+    - Branches
+      #+BEGIN_SRC
+      $ ls -1 .git/refs/heads/*
+      .git/refs/heads/gitlab_10.x_upgrade
+      .git/refs/heads/gitlab-ce-8.17
+      .git/refs/heads/gitlab-ce-9.1.4-defectFix
+      .git/refs/heads/master
+
+      $ cat .git/refs/heads/gitlab-ce-8.17
+      c63767d0b9b520f36a533237624dfaa1256b463c
+      #+END_SRC
+** Refs
+*** Refs
+    - tags
+      #+BEGIN_SRC
+      $ ls -1 .git/refs/tags/
+      gitlab-cookbook-for-10.7.3
+      gitlab-cookbook-initial
+      gitlab-cookbook-rebaseline
+
+      $ cat .git/refs/tags/gitlab-cookbook-for-10.7.3
+      f16b12027cef7052e09f3a483ace55999800ea5b
+      #+END_SRC
+    - =HEAD=
+      #+BEGIN_SRC
+      $ cat .git/HEAD
+      ref: refs/heads/gitlab_10.x_upgrade
+      #+END_SRC
+** Refs
+*** Refs
+    - remotes
+      #+BEGIN_SRC
+      $ ls -1 .git/refs/remotes/origin/*
+      .git/refs/remotes/origin/ara_test
+      .git/refs/remotes/origin/brjones_aci_network
+      .git/refs/remotes/origin/gitlab_10.x_upgrade
+      .git/refs/remotes/origin/gitlab-ce-8.17
+      .git/refs/remotes/origin/gitlab-ce-9.1.4-defectFix
+      .git/refs/remotes/origin/HEAD
+      .git/refs/remotes/origin/master
+
+      $ cat .git/refs/remotes/origin/ara_test
+      7130b7ee374ad9f7ba784ec0b0d0b86dc99f41d4
+      #+END_SRC
+** HEAD
+*** HEAD
+    - =HEAD= is a ref that points to where the commit currently checked out
+    - =HEAD= in a remote repository usually points to the default branch
+
+    #+BEGIN_SRC
+    $ cat .git/HEAD
+    ref: refs/heads/master
+    $ cat .git/refs/remotes/origin/HEAD
+    ref: refs/remotes/origin/REL2_0
+    #+END_SRC
+** Annotated tags
+*** Annotated tags
+    - A normal tag is just a "ref", pointing to a commit.
+      #+BEGIN_SRC shell
+        git tag Rel1.0 Rel1
+        cat .git/refs/tags/Rel1.0
+        git cat-file -t $(cat .git/refs/tags/Rel1.0)
+        git cat-file -p $(cat .git/refs/tags/Rel1.0)
+      #+END_SRC
+    - *Caveat*: tags and branches use different namespaces, so
+      temptation to tag the =Rel1= branch with =Rel1= would be
+      high. However, this causes confusion for many git tools, so
+      should be avoided.
+** Annotated tags
+*** Annotated tags
+    - An annotated tag is a separate git object, that records information specfic to the tag:
+      + Tag name; date; tagger; commit it's pointing to
+    - Advice is for annotated tags to be used for significant announcements/releases/snaphots.
+      #+BEGIN_SRC shell
+        git tag -a -m "Formal release of 1.0" \
+            Rel1.0.prod Rel1
+        cat .git/refs/tags/Rel1.0.prod
+        git cat-file -t $(cat .git/refs/tags/Rel1.0.prod)
+        git cat-file -p $(cat .git/refs/tags/Rel1.0.prod)
+      #+END_SRC
+** blame
+*** =blame=
+    - Identifies the commit, commit author and date for each line in a file.
+    - Doesn't give information for lines that have been removed or replaced.
+** Tag and commit signing
+*** Tag and commit signing and verification
+    - PGP/GnuPG (=gpg=): expects familiarity with public/private key encryption.
+    - Sign tags and commits with private key to assure integrity
+      #+BEGIN_SRC shell
+        git commit -Seibhear.geo@gmail.com \
+            -m "Update to information.md"
+        git cat-file -p $(cat .git/refs/heads/master)
+        git tag -s -u eibhear.geo@gmail.com \
+            -m "Release 2." Rel2.0 Rel2
+        git cat-file -p $(cat .git/refs/tags/Rel2.0)
+      #+END_SRC
+    - Verify commits and tags with public key
+      #+BEGIN_SRC
+      git tag -v Rel2.0
+      git log --show-signature -1
+      #+END_SRC
 * The Continental shelf
+** 
+*** Switch on the Sonar                                       :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.9
+    :BEAMER_env: block
+    :END:
+     file:./Loligo_vulgaris.jpg

+#+latex: {\tiny
+     By © Hans Hillewaert, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=385705
+#+latex: }
+** Git Objects -- blobs
+*** Blob (file)
+    A file
+    #+BEGIN_SRC shell
+      $ cat ~/.profile | git hash-object --stdin
+      c9db4591825bd7a918df686ff04aeb3a87d3bda0
+    #+END_SRC
+** Git Objects -- trees
+*** Tree
+    A listing of files and other tree objects containing the
+    following information on each: access mode (similar to UNIX
+    permissions); type (e.g. =tree=, =blob=); SHA1; file/directory
+    name
+    #+BEGIN_SRC shell
+      $ git cat-file -p \
+            2c4e4782bcb6b13a0e11b6961004dec8745e9d35
+      040000 tree bcd2824258ddf007dae7f88da7d727fb3894691b
+          Astro
+      100644 blob 94aea57573b92d9188a3df4cf748b60efd968803
+          MyHelloWorldBean.java
+      100644 blob c55118d1afb2be6a6d0f728814c084d54e97db14
+          MyHelloWorldServlet.java
+    #+END_SRC
+** Git Objects -- commits
+*** Commit
+    Information on a commit event:
+    - The SHA1 of the top-level tree of the project.
+    - The parent commit (or commits, if this commit is the result of
+      a merge)
+    - The details of the author of the code that is being applied
+      with the commit (including date and time)
+    - The details of the person who applied the commit (including date and time)
+    - The commit gpg signature, if present
+    - The commit comment
+** Git Objects -- commits
+*** Commit
+    #+BEGIN_SRC shell
+      $ git cat-file -p \
+            37c5611a177c9eafbd17e4302b6d644434b1042b
+      tree 40b6262f3f3f5fc8cb8a0c78ca558a683dfc2323
+      parent 42608808a973b8e0c4a4b0105c2317d81b12851f
+      parent 36d56f097ca81f06d77f46cbde3fc10cbf6639f9
+      author Master O'Theuniverse \
+          <master.otheuniverse@example.com> \
+          1529840879 +0100
+      committer Master O'Theuniverse \
+          <master.otheuniverse@example.com> \
+          1529840879 +0100
+
+      REV18_5 now live
+    #+END_SRC
+** Git Objects -- tags
+*** Tag
+    A tag points to a commit object, and an annotated tag contains
+    additional information
+    - What object it's pointing at and its type
+    - The name of the tag
+    - Who applied the tag (including date and time)
+    - A tag comment
+** Git Objects -- tags
+*** Tag
+    #+BEGIN_SRC shell
+      $ git cat-file -p \
+            88a4c18867ccb1d7c398f285460d8abab3964e75
+      object 66d8336c2770d0d1cea3dcb0175611edb5e69f69
+      type commit
+      tag Rel1.0.a
+      tagger Éibhear Ó hAnluain \
+          <eibhear.geo@gmail.com> \
+          1529847749 +0100
+
+      An annotated tag for the Rel1 release
+
+      $ git cat-file -t \
+            66d8336c2770d0d1cea3dcb0175611edb5e69f69
+      commit
+    #+END_SRC
+** "Content Addressable Filesystem"
+*** "Content Addressable Filesystem"
+    As the IDs of objects are based on their contents, they are
+    located in the git database according to that name
+    #+BEGIN_SRC shell
+      git rev-list --all --objects
+      git cat-file -p \
+          b5aea839bc89a0c7931af469ff9c145be18854d7
+      git cat-file -p \
+          b5aea839bc89a0c7931af469ff9c145be18854d7 | \
+          git hash-object --stdin
+      ls -l .git/objects/b5/aea839bc89a0c7931af469ff9c145be18854d7
+    #+END_SRC
 * The Deep trenches
+** 
+*** Exotic creatures                                          :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.7
+    :BEAMER_env: block
+    :END:
+     file:./Alvinella_pompejana01.jpg
+
+#+latex: {\tiny
+     By National Science Foundation (University of Delaware College of Marine Studies) - http://www.nsf.gov/od/lpa/news/press/01/pr0190.htm, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7123122
+#+latex: }
+** The reflog
+*** The reflog
+    - A log of all the changes to HEAD
+    - Local only: not involved in pulls, pushes or fetches.
+    - Useful for recovering accidentally removed commits
+    - Completely clear the reflog
+      : git reflog expire --expire=now \
+      :     --expire-unreachable=now --verbose --all
+** fsck and gc
+*** fsck and gc
+    - fsck :: Analyse connectivity of the objects in the git
+              database. Useful for finding objects that aren't of any
+              use any more.
+    - gc :: "Garbage collector". Compress and pack objects, remove
+            "danlging" and unreachable objects
+** Useful commands
+*** Useful commands
+    - Find the largest object in your git database
+      #+BEGIN_SRC shell
+        git cat-file \
+            --batch-check='%(objecttype) %(objectname) %(objectsize)' \
+            --batch-all-objects | sed -n 's/^blob //p' | \
+            sort -n --key=2
+      #+END_SRC
+    - List all objects in your git database
+      : git rev-list --all --objects
+    - Determine the filename related to a blob object
+      : git rev-list --objects --all | grep <objectID>
+    - Determine commits that reference that file
+      : git log --follow -- "<fileNameAndPath>"
+** Permanently removing a file from your git db
+*** Permanently removing a file from your git db
+    - e.g. contains password information, v. large file not required, etc.
+    - For each branch...
+      + Check it out
+        : git checkout <branch>
+      + Remove the file from all commits
+        #+BEGIN_SRC shell
+          git filter-branch --tree-filter \
+              'rm -f <filePathAndName>' \
+              --prune-empty HEAD
+        #+END_SRC
+      + Clean up the original refs
+        #+BEGIN_SRC shell
+          git for-each-ref --format="%(refname)" \
+              refs/original/ | \
+              xargs -n 1 git update-ref -d
+        #+END_SRC
+** Permanently removing a file from your git db
+*** Permanently removing a file from your git db
+    - ... then ...
+      - Clear out the reflog
+        : git reflog expire --expire-unreachable=now --all
+        The reflog maintains references to commits and objects you
+        may want to remove.
+      - Collect the garbage, regardless of age
+        : git gc --prune=now
+      - Sanity-check all objects
+        : git fsck --unreachable --no-reflogs
+** Other interesting concepts
+*** Other interesting concepts
+    - *Porcelain vs Plumbing*: The commands that we use vs the commands that *they* use.
+      + *Porcelain*: =init=, =clone=, =fetch=, =push=, =add=, =commit=, etc.
+      + *Plumbing*: =hash-object=, =cat-file=, =write-tree=, =count-objects=, etc.
+    - *submodules*: to link a separate git repository into yours
+    - *fast-import*: to import data into a git repository from other,
+      non-git sources (e.g. cvs, subversion, etc.)
+** Resources
+*** Resources
+    - The git book :: https://git-scm.com/book/en/v2/
+    - The git manual ::
+                        #+BEGIN_SRC shell
+                          git help --all
+                          git help merge
+                          git help cat-file
+                          man git-hash-object
+                        #+END_SRC
+    - Stack overflow :: https://stackoverflow.com/questions/tagged/git
+* Commands                                                         :noexport:
+  |   | add                      |
+  |   | add--interactive         |
+  |   | am                       |
+  | x | +annotate+               |
+  |   | apply                    |
+  |   | archive                  |
+  |   | bisect                   |
+  |   | bisect--helper           |
+  | + | blame                    |
+  |   | branch                   |
+  |   | bundle                   |
+  |   | cat-file                 |
+  |   | check-attr               |
+  |   | check-ignore             |
+  |   | check-mailmap            |
+  |   | check-ref-format         |
+  |   | checkout                 |
+  |   | checkout-index           |
+  |   | cherry                   |
+  |   | cherry-pick              |
+  |   | clean                    |
+  |   | clone                    |
+  |   | column                   |
+  |   | commit                   |
+  |   | commit-tree              |
+  | + | config                   |
+  |   | count-objects            |
+  |   | credential               |
+  |   | credential-cache         |
+  |   | credential-cache--daemon |
+  |   | credential-store         |
+  |   | daemon                   |
+  |   | describe                 |
+  |   | diff                     |
+  |   | diff-files               |
+  |   | diff-index               |
+  |   | diff-tree                |
+  |   | difftool                 |
+  |   | difftool--helper         |
+  | + | fast-export              |
+  | + | fast-import              |
+  |   | fetch                    |
+  |   | fetch-pack               |
+  | + | filter-branch            |
+  |   | fmt-merge-msg            |
+  |   | for-each-ref             |
+  |   | format-patch             |
+  | + | fsck                     |
+  | + | fsck-objects             |
+  | + | gc                       |
+  |   | get-tar-commit-id        |
+  |   | grep                     |
+  |   | hash-object              |
+  |   | help                     |
+  |   | http-backend             |
+  |   | http-fetch               |
+  |   | http-push                |
+  |   | imap-send                |
+  |   | index-pack               |
+  |   | init                     |
+  |   | init-db                  |
+  |   | instaweb                 |
+  |   | log                      |
+  |   | ls-files                 |
+  | + | ls-remote                |
+  |   | ls-tree                  |
+  |   | mailinfo                 |
+  |   | mailsplit                |
+  |   | merge                    |
+  |   | merge-base               |
+  |   | merge-file               |
+  |   | merge-index              |
+  |   | merge-octopus            |
+  |   | merge-one-file           |
+  |   | merge-ours               |
+  |   | merge-recursive          |
+  |   | merge-resolve            |
+  |   | merge-subtree            |
+  |   | merge-tree               |
+  |   | mergetool                |
+  |   | mktag                    |
+  | x | +mktree+                 |
+  |   | mv                       |
+  |   | name-rev                 |
+  |   | notes                    |
+  | + | pack-objects             |
+  |   | pack-redundant           |
+  |   | pack-refs                |
+  |   | patch-id                 |
+  |   | prune                    |
+  |   | prune-packed             |
+  |   | pull                     |
+  |   | push                     |
+  |   | quiltimport              |
+  |   | read-tree                |
+  | + | rebase                   |
+  |   | receive-pack             |
+  |   | reflog                   |
+  |   | relink                   |
+  |   | remote                   |
+  |   | remote-ext               |
+  |   | remote-fd                |
+  |   | remote-ftp               |
+  |   | remote-ftps              |
+  |   | remote-http              |
+  |   | remote-https             |
+  |   | remote-testsvn           |
+  |   | repack                   |
+  |   | replace                  |
+  |   | request-pull             |
+  | ? | rerere                   |
+  |   | reset                    |
+  |   | rev-list                 |
+  |   | rev-parse                |
+  |   | revert                   |
+  |   | rm                       |
+  |   | send-pack                |
+  |   | sh-i18n--envsubst        |
+  | x | +shell+                  |
+  |   | shortlog                 |
+  |   | show                     |
+  |   | show-branch              |
+  |   | show-index               |
+  |   | show-ref                 |
+  |   | stage                    |
+  |   | stash                    |
+  |   | status                   |
+  |   | stripspace               |
+  | + | submodule                |
+  |   | subtree                  |
+  |   | svn                      |
+  |   | symbolic-ref             |
+  |   | tag                      |
+  |   | unpack-file              |
+  |   | unpack-objects           |
+  |   | update-index             |
+  |   | update-ref               |
+  |   | update-server-info       |
+  |   | upload-archive           |
+  |   | upload-pack              |
+  |   | var                      |
+  |   | verify-commit            |
+  |   | verify-pack              |
+  |   | verify-tag               |
+  |   | web--browse              |
+  |   | whatchanged              |
+  |   | write-tree               |
+
+* Diagrams                                                         :noexport:
+** Diagram builder
+   #+name: rev-control-flow-builder
+   #+BEGIN_SRC emacs-lisp :results raw :colnames yes :var legend=rev-control-flow-legend nodes=rev-control-flow-elements graph=rev-control-flow-connections ranks=rev-control-flow-ranks
+     (org-dot-flow-chart nodes graph ranks legend nil)
+   #+END_SRC
+
+   #+RESULTS: rev-control-flow
+
+*** Flow legend
+    #+name: rev-control-flow-legend
+    | *node* | *label* | *colour* |
+    |--------+---------+----------|
+*** Flow elements
+    #+name: rev-control-flow-elements
+    | *node*  | *label* | *shape*   | *fillcolor* | *style* |
+    |---------+---------+-----------+-------------+---------|
+*** Flow connections
+    #+name: rev-control-flow-connections
+    | from    | to      | label | colour | style |
+    |---------+---------+-------+--------+-------|
+*** Flow ranks
+    #+name: rev-control-flow-ranks
+    | anchor  | node   |
+    |---------+--------|
+
+** Fast forward merge initial state diagram
+   #+name: fast-forward-initial-state-chart
+   #+BEGIN_SRC dot :file ./fast-forward-initial-state.png :var code=rev-control-flow-builder(legend=ff-initial-legend,nodes=ff-initial-elements,graph=ff-initial-connections,ranks=ff-initial-ranks)
+   $code
+   #+END_SRC
+
+   #+RESULTS: fast-forward-initial-state-chart
+   [[file:./fast-forward-initial-state.png]]
+
+*** Flow legend
+    #+name: ff-initial-legend
+    | *node* | *label* | *colour* |
+    |--------+---------+----------|
+*** Flow elements
+    #+name: ff-initial-elements
+    | *node*  | *label* | *shape*   | *fillcolor* | *style* |
+    |---------+---------+-----------+-------------+---------|
+    | commit1 | a8ebfae | circle    | green       |         |
+    | commit2 | 21ab34c | circle    | green       |         |
+    | commit3 | 785cd72 | circle    | green       |         |
+    | commit4 | f471562 | circle    | green       |         |
+    | commit5 | a642864 | circle    | green       |         |
+    | commit6 | 558628d | circle    | green       |         |
+    | commit7 | a3b95aa | circle    | green       |         |
+    | master  | master  | rectangle | yellow      |         |
+    | rel1    | Rel1    | rectangle | yellow      |         |
+    | rel2    | Rel2    | rectangle | yellow      |         |
+    |---------+---------+-----------+-------------+---------|
+*** Flow connections
+    #+name: ff-initial-connections
+    | from    | to      | label | colour | style |
+    |---------+---------+-------+--------+-------|
+    | commit2 | commit1 |       |        |       |
+    | commit3 | commit2 |       |        |       |
+    | commit4 | commit3 |       |        |       |
+    | commit5 | commit4 |       |        |       |
+    | commit6 | commit3 |       |        |       |
+    | commit7 | commit6 |       |        |       |
+    | master  | commit3 |       |        |       |
+    | rel1    | commit5 |       |        |       |
+    | rel2    | commit7 |       |        |       |
+    |---------+---------+-------+--------+-------|
+*** Flow ranks
+    #+name: ff-initial-ranks
+    | anchor  | node   |
+    |---------+--------|
+    | commit3 | master |
+    | commit5 | rel1   |
+    | commit7 | rel2   |
+    |---------+--------|
+
+** Fast forward merge completed state diagram
+   #+name: fast-forward-completed-state-chart
+   #+BEGIN_SRC dot :file ./fast-forward-completed-state.png :var code=rev-control-flow-builder(legend=ff-completed-legend,nodes=ff-completed-elements,graph=ff-completed-connections,ranks=ff-completed-ranks)
+   $code
+   #+END_SRC
+
+   #+RESULTS: fast-forward-completed-state-chart
+   [[file:./fast-forward-completed-state.png]]
+
+*** Flow legend
+    #+name: ff-completed-legend
+    | *node* | *label* | *colour* |
+    |--------+---------+----------|
+*** Flow elements
+    #+name: ff-completed-elements
+    | *node*  | *label* | *shape*   | *fillcolor* | *style* |
+    |---------+---------+-----------+-------------+---------|
+    | commit1 | a8ebfae | circle    | green       |         |
+    | commit2 | 21ab34c | circle    | green       |         |
+    | commit3 | 785cd72 | circle    | green       |         |
+    | commit4 | f471562 | circle    | green       |         |
+    | commit5 | a642864 | circle    | green       |         |
+    | commit6 | 558628d | circle    | green       |         |
+    | commit7 | a3b95aa | circle    | green       |         |
+    | master  | master  | rectangle | yellow      |         |
+    | rel1    | Rel1    | rectangle | yellow      |         |
+    | rel2    | Rel2    | rectangle | yellow      |         |
+    |---------+---------+-----------+-------------+---------|
+*** Flow connections
+    #+name: ff-completed-connections
+    | from    | to      | label | colour | style |
+    |---------+---------+-------+--------+-------|
+    | commit2 | commit1 |       |        |       |
+    | commit3 | commit2 |       |        |       |
+    | commit4 | commit3 |       |        |       |
+    | commit5 | commit4 |       |        |       |
+    | commit6 | commit3 |       |        |       |
+    | commit7 | commit6 |       |        |       |
+    | master  | commit5 |       |        |       |
+    | rel1    | commit5 |       |        |       |
+    | rel2    | commit7 |       |        |       |
+    |---------+---------+-------+--------+-------|
+*** Flow ranks
+    #+name: ff-completed-ranks
+    | anchor  | node   |
+    |---------+--------|
+    | commit5 | master |
+    | commit5 | rel1   |
+    | commit7 | rel2   |
+    |---------+--------|
+
+** Two-branch merge completed state diagram
+   #+name: two-branch-completed-state-chart
+   #+BEGIN_SRC dot :file ./two-branch-completed-state.png :var code=rev-control-flow-builder(legend=two-branch-completed-legend,nodes=two-branch-completed-elements,graph=two-branch-completed-connections,ranks=two-branch-completed-ranks)
+   $code
+   #+END_SRC
+
+   #+RESULTS: two-branch-completed-state-chart
+   [[file:./two-branch-completed-state.png]]
+
+*** Flow legend
+    #+name: two-branch-completed-legend
+    | *node* | *label* | *colour* |
+    |--------+---------+----------|
+*** Flow elements
+    #+name: two-branch-completed-elements
+    | *node*  | *label* | *shape*   | *fillcolor* | *style* |
+    |---------+---------+-----------+-------------+---------|
+    | commit1 | a8ebfae | circle    | green       |         |
+    | commit2 | 21ab34c | circle    | green       |         |
+    | commit3 | 785cd72 | circle    | green       |         |
+    | commit4 | f471562 | circle    | green       |         |
+    | commit5 | a642864 | circle    | green       |         |
+    | commit6 | 558628d | circle    | green       |         |
+    | commit7 | a3b95aa | circle    | green       |         |
+    | commit8 | f3ca059 | circle    | green       |         |
+    | master  | master  | rectangle | yellow      |         |
+    | rel1    | Rel1    | rectangle | yellow      |         |
+    | rel2    | Rel2    | rectangle | yellow      |         |
+    |---------+---------+-----------+-------------+---------|
+*** Flow connections
+    #+name: two-branch-completed-connections
+    | from    | to      | label | colour | style |
+    |---------+---------+-------+--------+-------|
+    | commit2 | commit1 |       |        |       |
+    | commit3 | commit2 |       |        |       |
+    | commit4 | commit3 |       |        |       |
+    | commit5 | commit4 |       |        |       |
+    | commit6 | commit3 |       |        |       |
+    | commit7 | commit6 |       |        |       |
+    | commit8 | commit5 |       |        |       |
+    | commit8 | commit7 |       |        |       |
+    | master  | commit8 |       |        |       |
+    | rel1    | commit5 |       |        |       |
+    | rel2    | commit7 |       |        |       |
+    |---------+---------+-------+--------+-------|
+*** Flow ranks
+    #+name: two-branch-completed-ranks
+    | anchor  | node   |
+    |---------+--------|
+    | commit8 | master |
+    | commit5 | rel1   |
+    | commit7 | rel2   |
+    |---------+--------|
+
+** Rebase merge completed state diagram
+   #+name: rebase-completed-state-chart
+   #+BEGIN_SRC dot :file ./rebase-completed-state.png :var code=rev-control-flow-builder(legend=rebase-completed-legend,nodes=rebase-completed-elements,graph=rebase-completed-connections,ranks=rebase-completed-ranks)
+   $code
+   #+END_SRC
+
+   #+RESULTS: rebase-completed-state-chart
+   [[file:./rebase-completed-state.png]]
+
+*** Flow legend
+    #+name: rebase-completed-legend
+    | *node* | *label* | *colour* |
+    |--------+---------+----------|
+*** Flow elements
+    #+name: rebase-completed-elements
+    | *node*  | *label* | *shape*   | *fillcolor* | *style* |
+    |---------+---------+-----------+-------------+---------|
+    | commit1 | a8ebfae | circle    | green       |         |
+    | commit2 | 21ab34c | circle    | green       |         |
+    | commit3 | 785cd72 | circle    | green       |         |
+    | commit4 | f471562 | circle    | green       |         |
+    | commit5 | a642864 | circle    | green       |         |
+    | commit6 | 5e8378c | circle    | green       |         |
+    | commit7 | 9076677 | circle    | green       |         |
+    | master  | master  | rectangle | yellow      |         |
+    | rel1    | Rel1    | rectangle | yellow      |         |
+    | rel2    | Rel2    | rectangle | yellow      |         |
+    |---------+---------+-----------+-------------+---------|
+*** Flow connections
+    #+name: rebase-completed-connections
+    | from    | to      | label | colour | style |
+    |---------+---------+-------+--------+-------|
+    | commit2 | commit1 |       |        |       |
+    | commit3 | commit2 |       |        |       |
+    | commit4 | commit3 |       |        |       |
+    | commit5 | commit4 |       |        |       |
+    | commit6 | commit5 |       |        |       |
+    | commit7 | commit6 |       |        |       |
+    | master  | commit5 |       |        |       |
+    | rel1    | commit5 |       |        |       |
+    | rel2    | commit7 |       |        |       |
+    |---------+---------+-------+--------+-------|
+*** Flow ranks
+    #+name: rebase-completed-ranks
+    | anchor  | node   |
+    |---------+--------|
+    | commit5 | master |
+    | commit5 | rel1   |
+    | commit7 | rel2   |
+    |---------+--------|
+* Snippets                                                         :noexport:
+** Removing file from all branches
+   #+BEGIN_SRC shell
+     for tag in $(git tag)
+     do
+       echo "${tag},$(git log --format="%H,\"%cn\",\"%ci\",\"%s\"" ${tag} | head -1)"
+     done | tee ../tag_list.csv
+     for branch in $(git branch -r | grep -v HEAD | sed 's/\ \ origin\///')
+     do
+       git checkout ${branch}
+     done
+     for branch in $(git branch | sed 's/^..//')
+     do
+       git checkout -q ${branch}
+       du -sk . | sed "s/\./${branch}/"
+     done | tee ../branch_sizes.out
+     for branch in $(git branch | sed 's/^..//')
+     do
+       git checkout ${branch}
+       git filter-branch --tree-filter 'rm -f largeInformation.md' --prune-empty HEAD
+       git for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git update-ref -d
+     done | tee ../cleanup.out
+     git reflog expire --expire-unreachable=now --all
+     git gc --prune=now
+     git fsck --unreachable --no-reflogs
+     for branch in $(git branch | sed 's/^..//')
+     do
+       git checkout -q ${branch}
+       du -sk . | sed "s/\./${branch}/"
+     done | tee ../branch_sizes_post_process.out
+   #+END_SRC
--- a/images/Alvinella_pompejana01.jpg
+++ b/images/Alvinella_pompejana01.jpg
--- a/images/Loligo_vulgaris.jpg
+++ b/images/Loligo_vulgaris.jpg
--- a/images/Naufragio_por_Gustavo_Gerdel.jpg
+++ b/images/Naufragio_por_Gustavo_Gerdel.jpg
--- a/images/bCardBackground.png
+++ b/images/bCardBackground.png
--- a/images/fast-forward-completed-state.png
+++ b/images/fast-forward-completed-state.png
--- a/images/fast-forward-initial-state.png
+++ b/images/fast-forward-initial-state.png
--- a/images/rebase-completed-state.png
+++ b/images/rebase-completed-state.png
--- a/images/two-branch-completed-state.png
+++ b/images/two-branch-completed-state.png
--- a/styles/e-reveal.css
+++ b/styles/e-reveal.css
@ -0,0 +1,34 @@
+.figure {
+    font-size: 35%;
+}
+
+p.subtitle {
+    font-size: 50%;
+}
+
+h2.email {
+    font-size: 70%;
+}
+
+section {
+    font-size: 80%;
+}
+
+pre,
+code {
+  font-size: 80%;
+  color: #000000;
+  background-color: #e0e0e0;
+  border-style: solid;
+  border-width: 1px;
+  border-color: #c0c0c0;
+}
+
+pre {
+  padding: 0.5em;
+}
+
+code {
+  padding-right: 1px;
+  padding-left: 1px;
+}
--- a/styles/e-reveal.css~
+++ b/styles/e-reveal.css~
@ -0,0 +1,11 @@
+.figure {
+    font-size: 35%;
+}
+
+p.subtitle {
+    font-size: 50%;
+}
+
+h2.email {
+    font-size: 70%;
+}
--- a/styles/gridding.css
+++ b/styles/gridding.css
@ -0,0 +1,43 @@
+
+.bordered {
+    border: #000000;
+    border-style: solid;
+}
+
+.e-frame {
+    font-size: 70%;
+}
+
+.gridded_frame_with_columns {
+    display: flex;
+    flex-flow: row;
+}
+
+.one_of_2_columns {
+    width: 50%;
+}
+
+.one_of_3_columns {
+    width: 33%;
+}
+
+.column_with_rows {
+    display: flex;
+    flex-grow: auto;
+    flex-flow: column;
+}
+
+.row_with_columns {
+    display: flex;
+    flex-flow: row;
+}
+
+.gridded_frame_with_rows {
+    display: flex;
+    flex-flow: column;
+}
+
+.one_of_2_rows {
+    height: 50%;
+}
+