github - git training slides: foundations
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Git FoundationsAn exploration of the Git toolbox
Offi
cial
trai
ning
cur
ricul
um v
3.1.
0©
201
2, G
itHub
, Inc
.
Hello!
Matthew McCullough
@matthewmccull
Ma!hew who?‣Open source contributor‣Build tool book co-author‣Continuous integration book co-author‣5 year Git evangelist‣VP of Training at GitHub
Welcome
‣Questions, Pacing‣Ask questions at any time. Don't wait!‣Suggest course pacing slowing/speeding up
GitWhere’s this coming from?
Git
Git?
Open Source
Git?
bash scripts � C code
Git?
≉
Git-nounBritish Slang. an unpleasant
or contemptible person
-Oxford English Dictionary
“
”
I'm an egotistical bastard, and I name
all my projects after myself.
First Linux, now git.-Linus Torvalds
“
”
GitWhat is this thing?
GIT - the stupid content tracker
"git" can mean anything, depending on
your mood.
* random three-letter combination that
is pronounceable, and not actually
used by any
common UNIX command. The fact that it
is a mispronunciation of "get" may or
may not be
relevant.* stupid. contempti
ble and despicable. simple. Take your
pick from the dictionary of
slang.* "global informati
on tracker": you're in a good mood, an
d it actually works for you.
Angels sing, and a light suddenly fill
s the room.
* "goddamn idiotic truckload of sh*t":
when it breaks
Git is a fast, scalable, distributed r
evision control system with an unusual
ly rich
command set that provides both high-le
vel operations and full access to inte
rnals.
Git is an Open Source project covered
by the GNU General Public License. It
was originally
written by Linus Torvalds with help of
a group of hackers around the net. It
is currently
maintained by Junio C Hamano.
“
”
file trackercontent
Git?
centralized version control systems have matured
CVS
Subversion
PVCS
Perforce
ClearCaseSource
Safe
RCS
Folders
Git?
small improvements, but noradical innovation
Git?
Linus?
Git?
I did end up using CVS for 7 years at a commercial
company and I hate it with a passion...
The slogan of Subversion for a while was
"CVS done right"... and if you start with that
kind of slogan, there's nowhere you can go.
There is no way to do CVS right.-Linus Torvalds
“
”
VCS reboot
Git?
50% Distributed Version Control
Git?
50% Git Concepts
with
1997code co-op
2001arch
2003monotone
2003SVK
2003darcs
2005bazaar
2005mercurial
2005git
time to mature
most unique improvements
largest DVCS user base
SetupTesting Git
Setting up Git
Check your Git version... git --version
SetupWhat is a Git install?
Setting up Git
binaries on your $PATH
UsingCreating a repository
Creating A Repository
# Green field project$ git init newproject$ cd newproject# ...start coding
Creating A Repository
‣Create our first repository
Creating A Repository
or if you already have source code
Creating A Repository
# Legacy project tree$ cd existingproject$ git init
# Add all the code$ git add .$ git commit -m”Initial import”
UsingWhat’s in .git?
Contents of .git
.git!"" COMMIT_EDITMSG!"" HEAD!"" MERGE_RR!"" config!"" description!"" hooks# !"" pre-commit.sample# $"" update.sample!"" index!"" info# $"" exclude!"" logs# !"" HEAD# $"" refs# $"" heads# $"" master!"" objects# !"" 54# # $"" 3b9bebdc6bd5c4b22136034a95dd097a57d3dd# !"" info# $"" pack!"" refs !"" heads # $"" master $"" tags
Three stage thinking
‣Explore the .git folder
ConfigurationDisplay
Configuring Git
Query existing configuration
Configuring Git
All entries
Configuring Git
#List all config valuesgit config --list
Configuring Git
Single entry
Configuring Git
#Query effective value of a single keygit config section.keygit config section.subsection.key
Configuring Git
#Show a specific config valuegit config user.namegit config user.email
ConfigurationLayers
Config Targets
git config --system#Saves to /etc/gitconfig
Config Targets
git config --global#Saves to ~/.gitconfig
Config Targets
git config --local#Saves to .git/config
Configuring Git
#Configure a setting in a .git repository
git config __________git config --local __________
#Configure a setting in the user's home dir
git config --global __________
#Configure a setting in the Git install dir# e.g. /usr/local/Cellar/git/1.7.x/etc/gitconfig
git config --system __________
Config Targets
Git configuration reading & writing
targets local by default
ConfigurationInheritance
Config Inheritance
Query existing configuration by layer
Config Inheritance
#Query a single key in a single layergit config --<WHERE> section.keygit config --<WHERE> section.subsection.key
Config Inheritance
#List all system config valuesgit config --system --list
Config Inheritance
#List all global config valuesgit config --global --list
Config Inheritance
#List all local config valuesgit config --local --list
Config Inheritance
#List effective config valuesgit config --list
ConfigurationSet user identity
Set User Identity
any config at any layer
Set User Identity
#List the current config git config --global user.name "Fird Birfle"git config --global user.email "fird@birfle.com"
Set User Identity
just a string
Set User Identity
user identity
Set User Identity
user identityauthenticationnot
Set User Identity
user identityauthenticationauthorization not
ConfigurationDisplay color
Set Console Color
console color
Set Console Color
git config --global color.ui always
Set Console Color
git log \ --graph \ --decorate \ --simplify-by-decoration \ --abbrev-commit \ --date=relative \ --pretty=oneline \ --all
Configuring Git
git log \ --graph \ --decorate \ --simplify-by-decoration \ --abbrev-commit \ --date=relative \ --pretty=oneline \ --all \ | more
Set Console Color
Bleh!
Set Console Color
output destination detection
Set Console Color
git config --global color.ui auto
# or the identical effect with...git config --global color.ui true
Set Console Color
git log \ --graph \ --decorate \ --simplify-by-decoration \ --abbrev-commit \ --date=relative \ --pretty=oneline \ --all \ | more
Set Console Color
when you need itColor
Set Console Color
Set Console Color
only when you need itColor
ConfigurationLine endings
Line Endings
line endings
Line Endings
VS
Line Endings
VSLF
CRLF
Line Endings
default is to do nothing
Line Endings
http://help.github.com/dealing-with-lineendings/
Line Endings
#Force files to be LF in the repo,# even on Mac/Linuxgit config --global core.autocrlf input
#Force Windows to convert to platform# on checkout and to LF on commitgit config --global core.autocrlf true
Line Endings
#Force files to be LF during `add`git config --global core.autocrlf input
#Force Windows to convert to CRLF# on checkout and to LF on `add`git config --global core.autocrlf true
warn about conversion
Line Endings
#Never complain about line ending conversiongit config --global core.safecrlf false
#Warn, but allow line ending conversion to proceed#(the default)git config --global core.safecrlf warn
#Do not allow line ending conversion to proceedgit config --global core.safecrlf true
ConfigurationSecure Sockets Host (SSH)
Configuring SSH
‣Generate an ssh key pair
Configuring SSH
ssh key pair
Configuring SSH
$ ssh-keygen -t rsa -C”For GitHub”
Configuring SSH
$ ssh-keygen -t rsa -C”For GitHub”
Configuring SSH
Configuring SSH
# Verify the files were created
$ cd ~/.ssh$ ls
Configuring SSH
Configuring SSH
‣id_rsa is the private half of the key‣Keep this uncompromisingly secret
‣id_rsa.pub is the public half of the key‣Give this away freely
Configuring SSH
#GitHub sanity testssh -T git@github.com
> Hi matthewmccullough! You've successfully authenticated, but GitHub does not provide shell access.
Configuring SSH
#GitHub sanity test with verbose SSHssh -v git@github.com
>OpenSSH_5.2p1, OpenSSL 0.9.8l 5 Nov 2009debug1: Reading configuration data /Users/mccm06/.ssh/configdebug1: Reading configuration data /etc/ssh_configdebug1: Connecting to github.com [207.97.227.239] port 22.debug1: Connection established.debug1: identity file /Users/mccm06/.ssh/identity type -1debug1: identity file /Users/mccm06/.ssh/id_rsa type 1debug1: identity file /Users/mccm06/.ssh/id_dsa type 2...debug1: Host 'github.com' is known and matches the RSA host key.debug1: Found key in /Users/mccm06/.ssh/known_hosts:3debug1: ssh_rsa_verify: signature correct...debug1: Trying private key: /Users/mccm06/.ssh/identitydebug1: Offering public key: /Users/mccm06/.ssh/id_rsadebug1: Remote: Forced command: gerve matthewmccullough
Using GitThree Stage Thinking
Three stage thinking
‣Edit‣Add‣Commit
Three stage thinking
Working Staging Repo
add
commit
edit
Three stage thinking
‣shopping cart‣put things in‣take things out‣purchase at register
Three stage thinking
Three stage thinking
‣database transaction‣update values‣insert rows‣delete rows‣commit transaction
Three stage thinking
only one staging area
Three stage thinking
Working Staging Repo
add
commit
edit
SetupCommit Message Editor
Commit Message Editor
✓? Used the VI editor?
Commit Message Editor
Iy;WQ
Commit Message Editor
an alternate editor?
Commit Message Editor
$EDITOR environment variable
Option 1
Commit Message Editor
$ export EDITOR=<AnEditorOnYourPath>
Option 1
Commit Message Editor
GitPad wraps Notepad (or $EDITOR)
Option 2
Commit Message Editor
http://github.com/github/GitPad
Option 2
Commit Message Editor
Run GitPad...registers & wraps Notepad as the editor
Option 2
Commit Message Editor
Git-specific configuration option
Option 3
Commit Message Editor
#for TextMate on Macgit config --global core.editor "mate -w"
#for Notepad2 on Windowsgit config --global core.editor "notepad2.exe"
#for emacs on Linuxgit config --global core.editor "emacs"
Option 3
Commit Message Editor
Option 3
Commit Message Editor
‣Toggle to alternate editor
‣Make a commit
‣Test that the new editor pops up
Usage BasicsAdding & committing code
Three stage thinking
$ vi first.html
$ git status$ git add first.html$ git commit -m”First commit”
Three stage thinking
‣Write a sample HTML or TXT file
‣Inspect Git’s status
‣Add code (stage it)
‣Commit code
Usage BasicsDiff-ing changes
Three stage thinking
What has changed that we haven’t committed?
Three stage thinking
# Show the unstaged changes$ git diff
Three stage thinking
Working Staging Repo
$ git diff
Three stage thinking
# Show the staged changes$ git diff --staged
Three stage thinking
Working Staging Repo
$ git diff --staged
Three stage thinking
# Show uncommitted changes$ git diff HEAD
Three stage thinking
Working Staging Repo
$ git diff HEAD
Usage BasicsLimiting diff output
Limiting Diff Output
Word changes instead of entire lines?
Limiting Diff Output
git diff --color-words
Limiting Diff Output
$ git diffdiff --git a/first.txt b/first.txtindex cbb1543..e99dea9 100644--- a/first.txt+++ b/first.txt@@ -1,4 +1,4 @@-//Round the rugged rock+//Round the ragged rock
$ git diff --color-wordsdiff --git a/first.txt b/first.txtindex cbb1543..e99dea9 100644--- a/first.txt+++ b/first.txt@@ -1,4 +1,4 @@//Round the ruggedragged rock
Limiting Diff Output
git diff --word-diff
Limiting Diff Output
$ git diffdiff --git a/first.txt b/first.txtindex cbb1543..e99dea9 100644--- a/first.txt+++ b/first.txt@@ -1,4 +1,4 @@-//Round the rugged rock+//Round the ragged rock
$ git diff --word-diffdiff --git a/first.txt b/first.txtindex cbb1543..e99dea9 100644--- a/first.txt+++ b/first.txt@@ -1,4 +1,4 @@//Round the [-rugged-]{+ragged+} rock
Usage BasicsWhitespace diff
Limiting Diff Output
whitespace suppressed?
Limiting Diff Output
refactoring review
Limiting Diff Output
git diff -w
Limiting Diff Output
$ git diffdiff --git a/first.txt b/first.txtindex 09195c0..f2c3243 100644--- a/first.txt+++ b/first.txt@@ -1,4 +1,4 @@-//Foo-//Bar-//Baz+ //Foo+// Bar+//Baz▊
$ git diff -w$
Usage BasicsLimiting diff by type
Limiting Diff Output
# Added (A)# Copied (C)# Deleted (D)# Modified (M)# Renamed (R)# Type changed (T)# Unmerged (U)# Unknown (X)# Pairing Broken (B)
# Only show changes in added filesgit diff --diff-filter=A
Limiting Diff Output
# Added (A)# Copied (C)# Deleted (D)# Modified (M)# Renamed (R)# Type changed (T)# Unmerged (U)# Unknown (X)# Pairing Broken (B)
# Only show changes in modified filesgit diff --diff-filter=M
Limiting Diff Output
# Added (A)# Copied (C)# Deleted (D)# Modified (M)# Renamed (R)# Type changed (T)# Unmerged (U)# Unknown (X)# Pairing Broken (B)
# Only show changes in added or modified filesgit diff --diff-filter=AM
Limiting Diff Output
$ git status -s -u
D READMEMM first.txt
$ git diff --diff-filter=M
diff --git a/first.txt b/first.txtindex 71b55ef..14e4853 100644--- a/first.txt+++ b/first.txt@@ -1,3 +1,3 @@-//Foo //Bar+//Baz
Only first.txt is reported
Usage BasicsReviewing history
Three stage thinking
view history of commits
Three stage thinking
# Show all historygit log
Three stage thinking
# Show all history with filenamesgit log --stat
Three stage thinking
# Show all history with patchesgit log --patchgit log -p
Three stage thinking
# Limit the output entriesgit log -1git log -3git log -5
Three stage thinking
# Control the output formatgit log --pretty=full
Three stage thinking
# Control the output formatgit log --pretty=fuller
Three stage thinking
# Control the output formatgit log --pretty=email
Three stage thinking
# Control the output formatgit log --pretty=raw
Three stage thinking
# Control the output formatgit log --pretty=format:<pattern>
Three stage thinking
# Limit the output to added filesgit log --diff-filter=A
Usage Basics+Ignoring files
Ignoring Files
Untracked TrackedUnmodified
TrackedModified
TrackedStaged
Ignored
commit
add
edit
add
rm
ignore
Ignoring Files
suppressing files from being reported as untracked
Ignoring Files
glob patterns
Ignoring Files
$ vim .gitignore
#Add glob patterns, one per line*.log*.tmp
Ignoring Files
in-memory recursive evaluation
Ignoring Files
$ vim .gitignore
#Add glob patterns, one per line*.log*.tmptargetoutput/!special.log
Ignoring Files
‣ Ignore files via local .gitignore
Usage Basics+Open source .gitignores
Open Source Ignores
Preconfigured .gitignore files
Open Source Ignores
http://github.com/github/gitignore
copy and paste(the one time it’s OK to do it)
Usage Basics+Global ignores
Global Ignore
Global .gitignore ?
Global Ignore
off by default
Global Ignore
$ git config --global core.excludesfile "~/.gitignore"
Global Ignore
$ vim ~/.gitignore
# Operating system and editor temp files# Generally redundant over project .gitignoresthumbs.db.DS_Store
Global Ignore
‣ Ignore files via global ~/.gitignore
Usage Basics+Removing files
The Git File Workflow
Untracked TrackedUnmodified
TrackedModified
TrackedStaged
Ignored
commit
add
edit
add
rm
ignore
The Git File Workflow
Removing Files
The Git File Workflow
# Directly remove & stage$ git rm <FILENAME>
The Git File Workflow
# Remove with OS or tool,# not integrated with Git$ rm <FILENAME>
# Staging area says it is# deleted but not staged$ git status
# Put deletion into staging$ git rm <FILENAME>
The Git File Workflow
# Remove with OS or tool# then follow up with git add$ rm <FILENAMES>$ git add -u .
The Git File Workflow
‣ Remove files
Usage Basics+Moving files
The Git File Workflow
Untracked TrackedUnmodified
TrackedModified
TrackedStaged
Ignored
commit
add
edit
add
rm
ignore
The Git File Workflow
Moving Files
The Git File Workflow
# Directly move & stage$ git mv <FILENAME> <NEWFILENAME>
The Git File Workflow
# Move with OS or tool,mv <FILENAME> <NEWFILENAME># Then follow up with git addgit add -A .
The Git File Workflow
‣ Rename (move) files
‣ View history of the move
Usage Basics+Similarity index
Similarity Index
no "move" primitive
Similarity Index
“similarity index”
Similarity Index
score of sameness
Usage Basics+Similarity index for moves
Similarity Index
# Move with OS or tool,$ mv <FILENAME> <NEWFILENAME>
# Follow up by staging everything$ git add -A .
# Renames showinggit status
# No renames showing?git log --stat
why no renames in history?
Similarity Index
# Renames showngit log --stat -M
Similarity Index
‣ Rename (move) files with changes
‣ Essentially, a refactoring workflow
Usage Basics+Similarity index for copies
Similarity Index
# Copies & renames shown# (superset of -M)git log --stat -C
Similarity Index
‣Copy a file to a new filename
‣ Add and commit it
‣ Log it using our -C option
“For performance reasons, by
default, -C option finds copies only if the original file
of the copy was modified in
the same changeset. ”
Similarity Index
‣Modify a file and copy it (in the same commit)
‣ Log using the -C option
“ The --find-copies-harder flag makes the
command inspect unmodified files as
candidates for the source of copy. This
is a very expensive operation for large
projects, so use it with caution. Giving
more than one -C option has the same
effect.”
Similarity Index
# Copies & renames shown# (superset of -M)git log --stat -C -Cgit log --stat --find-copies-harder
Similarity Index
‣ Log the same file using our -C -C option
Usage Basics+Similarity index for blame
Similarity Index
# File authoring showngit blame rerere.c
Similarity Index
# True source of code showngit blame rerere.c -C
Similarity Index
5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 1) #include "cache.h"c455c87c (Johannes Schindelin 2008-07-21 19:03:49 +0100 2) #include "string-list.h"5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 3) #include "rerere.h"5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 4) #include "xdiff-interface.h"dea4562b (Junio C Hamano 2009-12-25 15:51:32 -0800 5) #include "dir.h"dea4562b (Junio C Hamano 2009-12-25 15:51:32 -0800 6) #include "resolve-undo.h"dea4562b (Junio C Hamano 2009-12-25 15:51:32 -0800 7) #include "ll-merge.h"8588567c (Junio C Hamano 2010-01-16 23:28:46 -0800 8) #include "attr.h"5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 9) ac49f5ca (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 10) #define RESOLVED 0ac49f5ca (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 11) #define PUNTED 1ac49f5ca (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 12) #define THREE_STAGED 2ac49f5ca (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 13) void *RERERE_RESOLVED = &RERERE_RESOLVED;ac49f5ca (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 14) 5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 15) /* if rerere_enabled == -1, fall back to detection of .git5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 16) static int rerere_enabled = -1;5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 17) 5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 18) /* automatically update cleanly resolved paths to the inde5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 19) static int rerere_autoupdate;5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 20) 5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 21) static char *merge_rr_path;5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 22) 90056966 (SZEDER Gábor 2009-02-14 23:21:04 +0100 23) const char *rerere_path(const char *hex, const char *file)5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 24) {90056966 (SZEDER Gábor 2009-02-14 23:21:04 +0100 25) return git_path("rr-cache/%s/%s", hex, file);5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 26) }5b2fd956 (Stephan Beyer 2008-07-09 14:58:57 +0200 27)
Similarity Index
5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 1) #include "cache.h"c455c87c rerere.c (Johannes Schindelin 2008-07-21 19:03:49 +0100 2) #include "string-list.h"5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 3) #include "rerere.h"5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 4) #include "xdiff-interface.h"dea4562b rerere.c (Junio C Hamano 2009-12-25 15:51:32 -0800 5) #include "dir.h"dea4562b rerere.c (Junio C Hamano 2009-12-25 15:51:32 -0800 6) #include "resolve-undo.h"dea4562b rerere.c (Junio C Hamano 2009-12-25 15:51:32 -0800 7) #include "ll-merge.h"8588567c rerere.c (Junio C Hamano 2010-01-16 23:28:46 -0800 8) #include "attr.h"5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 9) ac49f5ca rerere.c (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 10) #define RESOLVED 0ac49f5ca rerere.c (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 11) #define PUNTED 1ac49f5ca rerere.c (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 12) #define THREE_STAGED 2ac49f5ca rerere.c (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 13) void *RERERE_RESOLVED = &RERERE_RESOLVED;ac49f5ca rerere.c (Martin von Zweigbergk 2011-02-16 05:47:44 -0500 14) b4372ef1 builtin-rerere.c (Johannes Schindelin 2007-07-06 13:05:59 +0100 15) /* if rerere_enabled == -1, fall back to detection of .gitb4372ef1 builtin-rerere.c (Johannes Schindelin 2007-07-06 13:05:59 +0100 16) static int rerere_enabled = -1;b4372ef1 builtin-rerere.c (Johannes Schindelin 2007-07-06 13:05:59 +0100 17) 121c813f builtin-rerere.c (Junio C Hamano 2008-06-22 02:04:31 -0700 18) /* automatically update cleanly resolved paths to the inde121c813f builtin-rerere.c (Junio C Hamano 2008-06-22 02:04:31 -0700 19) static int rerere_autoupdate;121c813f builtin-rerere.c (Junio C Hamano 2008-06-22 02:04:31 -0700 20) 658f3650 builtin-rerere.c (Johannes Schindelin 2006-12-20 17:39:41 +0100 21) static char *merge_rr_path;658f3650 builtin-rerere.c (Johannes Schindelin 2006-12-20 17:39:41 +0100 22) 90056966 rerere.c (SZEDER Gábor 2009-02-14 23:21:04 +0100 23) const char *rerere_path(const char *hex, const char *file)5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 24) {90056966 rerere.c (SZEDER Gábor 2009-02-14 23:21:04 +0100 25) return git_path("rr-cache/%s/%s", hex, file);5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 26) }5b2fd956 rerere.c (Stephan Beyer 2008-07-09 14:58:57 +0200 27)
NetworkOffline design
Offline
‣ Local repository is a full copy of the remote
‣Clone fetches all branches and tags
‣Almost all activities happen offline (local disk)
‣Offline activities are push-ed to remotes
More available connectivity
More demand to work without connectivity?
Offline
nice benefit,but wrong reason
Offline
batched network access
Offline
Offline
Checkout a branchAdd changesCommit changesBranch changesLog historyGrep historyStash pending changesTag a commitRemove a fileMerge a branchRewrite history
Offline
give up incremental revision numbers
Offline
‣ Using every command offline
NetworkCloning protocols
Cloning Repositories
‣Git supports many cloning protocols‣file‣git‣ssh‣http
Cloning Repositories
‣file‣git clone file://myrepos/project‣git clone /myrepos/project
Cloning Repositories
‣git‣git clone git://server/project.git
Cloning Repositories
‣ssh‣ git clone git+ssh://user@server:project.git
‣ git clone user@server:project.git
Cloning Repositories
‣http (dumb)‣ git clone http://server/project.git‣ git clone https://server/project.git
Cloning Repositories
‣http (smart)‣git clone http://server/project.git‣git clone https://server/project.git
Cloning Repositories
‣ Clone hellogitworld
‣ git clone
NetworkProxy servers
Cloning Repositories
‣Git Configuration‣ git config --global http.proxy “<URL>”
NetworkSpeed
‣git: git‣hg: mercurial‣bzr: bazaar
data from http://whygitisbetterthanx.com/#git-is-fast
git svn
Init
git svn
Status
git svn
Diff
git svn
Tag
git svn
Log
git svn
Commit (Lg)
git svn
Commit (Sm)
git c svn c
Branch
Speed
Speed
‣ Add, commit and push 1000 files
NetworkNamespaces
Namespaces
Local Remote Upstream
Namespaces
#List local branchesgit branch
Namespaces
Local Remote Upstream
Namespaces
#List remote branchesgit branch -r
Namespaces
Local Remote Upstream
Namespaces
#List all branchesgit branch -a
Namespaces
Local Remote Upstream
Namespaces
#List upstream branchesgit ls-remote origin
Namespaces
Local Remote Upstream
NetworkNamespace operations
Namespaces
Local Remote Upstream
commit
fetch
push
clone clone clone
push
pull pull pull
NetworkThe commit lifecycle
Namespaces
Commit
Push
Pull
Namespaces
‣git commit
‣ Transactionally save code snapshot‣Commit to local branch‣Operate on local disk
Namespaces
Commit
Push
Pull
Namespaces
‣git push <remote>
‣Send code to an upstream server‣Update remote branches
Namespaces
Commit
Push
Pull
Namespaces
‣git pull <remote>
‣ Retrieve upstream objects‣ Update remote branch‣Merge changes into local branch‣ Commit the merge to the local branch
Namespaces
Local Remote Upstream
commit
fetch
push
clone clone clone
push
pull pull pull
NetworkRemotes
Remotes
Remotes are just symbolic names
Remotes
You can have as many as you like
Remotes
The default name is origin if you’ve cloned
Remotes
Remote-tracking branches are locally immutable (conceptually)
Remotes
Local Remote Upstream
Remotes
‣ Adding remotes
‣ Fetching from remotes (upstream)
NetworkPruning deletions
‣ Purge remote branches that have been removed from an upstream repository
‣ git remote prune <REMOTENAME>
Remotes
‣Deleting upstream branches
‣Pruning locally
ArchitecturePlumbing and Porcelain
Plumbing and Porcelain
Command Composition
Plumbing is the set of low level utilities
Command Composition
Porcelain is the set of end user commands
Command Composition
Porcelain is comprised of plumbing
Command Composition
Command Composition
git-add git-am git-archive git-bisect git-branch git-bundle git-checkout git-cherry-pick git-citool git-clean git-clone git-commit
git-describe git-diff git-fetch git-format-patch git-gc git-grep git-gui git-init git-log git-merge git-mv git-notes git-pull git-push git-
rebase git-reset git-revert git-rm git-shortlog git-show git-stash git-status git-submodule git-tag gitk git-config git-fast-export git-fast-import git-filter-branch git-lost-found git-mergetool git-pack-refs git-prune git-reflog git-relink git-remote git-repack git-replace git-repo-config git-annotate git-blame git-cherry git-count-objects
git-difftool git-fsck git-get-tar-commit-id git-help git-instaweb git-merge-tree git-rerere git-rev-parse git-show-branch git-verify-tag
git-whatchanged git-archimport git-cvsexportcommit git-cvsimport git-cvsserver git-imap-send git-quiltimport git-request-pull git-send-
email git-svnPo
rcel
ain
git-apply git-checkout-index git-commit-tree git-hash-object git-index-pack git-merge-file git-merge-index git-mktag git-mktree git-pack-objects git-prune-packed git-read-tree git-
symbolic-ref git-unpack-objects git-update-index git-update-ref git-write-tree git-cat-file git-diff-files git-diff-index git-diff-tree git-for-each-ref git-ls-files git-ls-remote git-ls-tree git-merge-base git-name-rev git-pack-redundant git-rev-list git-show-index git-show-ref git-tar-tree git-unpack-file git-var git-verify-pack git-daemon git-fetch-pack git-http-backend git-send-pack git-update-server-info git-http-fetch git-http-push git-parse-remote git-receive-pack git-shell git-upload-archive git-upload-pack git-check-attr git-check-ref-
format git-fmt-merge-msg git-mailinfo git-mailsplit git-merge-one-file git-patch-id git-peek-remote git-sh-setup git-stripspace
Plum
bing
pull is comprised of fetch + merge
Command Composition
checkout -b is comprised of branch + checkout
Command Composition
log HEAD is comprised of rev-parse + log
Command Composition
AliasesCommand shortcuts
Aliases
‣Shortcuts for common commands
‣Create your own recipe
‣Largely the same as shell aliases
Aliases
# Alias for status as 's'git config --global alias.s "status -u -s"
Aliases
‣ Add an alias
Aliases
# Alias for log with file name as 'l'git config --global alias.l "log --stat -C"
Aliases
# Alias showing all branches to 'br'git config --global alias.br "branch -a"
Aliases
# Alias for commit-no-staging to 'cns'git config --global alias.cns "commit -a"
Aliases
# Alias for shell pull then push to 'sync'$ git config --global alias.sync "!git pull && git push"
Aliases
# Alias for crummy-commit-file-quick$ git config --global alias.ccfq "!sh -c 'git add $1 && git commit -m\"Placeholder\"' -"
Aliases
‣ Matthew's Aliases
‣ https://github.com/matthewmccullough/git-workshop/blob/master/workbook/examples/config/.gitconfig
ArchitectureStorage
Typical SCMs use delta storage
Storage
CVS / Subversion / darcs / Mercurial
Storage
Storage
v1 v2 v3 v4
File A
File B
File C
File A
File B File B
File C
v5
File A
File BFile B
Δ Δ
ΔΔ ΔΔΔ
Checkin
Checkin Checkin Che
ckin
Che
ckin
Che
ckin
Che
ckin
Che
ckin
Check
in
Checkin
Checkin
Delta storage gets slower as the history of a file gets longer
Storage
Git uses DAG storage
Storage
Directed Acyclic Graph
Storage
Storage
Copy of the entire tree per checkin
Storage
cp -r srcfolder srcfolder.prev
Storage
Why?
Storage
Storage
v1 v2 v3 v4
File A
File B
File C
File A
File B File B
File C
v5
File A
File BFile B
File A File A
File C File C File C
hard link to existing identical blobs
Storage
Storage
v1 v2 v3 v4
File A
File B
File C
File A
File B File B
File C
v5
File A
File BFile B
File A File A
File C File C File Cß
zlib deflates each blob at commit
Storage
Storage
v1 v2 v3 v4
File A
File B
File C
File A
File B File B
File C
v5
File A
File BFile B
File A File A
File C File C File C
zlib deflates the entire repo
Storage
Storage
v1 v2 v3 v4
File A
File B
File C
File A
File B File B
File C
v5
File A
File BFile B
File A File A
File C File C File C
Storage
2100 MB became 205 MB
Act I
ArchitectureHashes
Hashes
centralized VCSs use sequential revision numbers
Hashes
Git uses a SHA-1 hash
Hashes
40 hex characters (20 bytes)
Hashes
9AB223D28B1AA46EF1780B22F304982E39872C34
Hashes
Hashes
9AB223D28B1AA46EF1780B22F304982E39872C34
<html><body>
<p>This is a test</p><img src="http://ai.com/icon.gif">
</body></html>
9AB223D28B1AA46EF1780B22F304982E39872C34
use as little of it as is unique
Hashes
ArchitectureHash shortcuts
commitish & treeish
Hashes
commitish
Hashes
= shorthand for commit hashes
treeish
Hashes
= shorthand for tree hashes
9AB22Fa certain commit
Hashes
9AB22F^one commit before a certain commit
Hashes
9AB22F^^two commits before a certain commit
Hashes
9AB22F~5five commits before a certain commit
Hashes
9AB223..56CD77between these two commits
Hashes
HEADthe most recent commit on this branch
Hashes
HEAD^one commit before the most recent commit
Hashes
HEAD~2two commits before the most recent commit
Hashes
HEAD..HEAD^^^between the given recent commits
Hashes
masterthe most recent commit on this branch
Hashes
master^^two commits before the most recent commit on this branch
Hashes
master~5five commits before the most recent commit on this branch
Hashes
remotes/origin/masterthe most recent commit on this remote tracking branch
Hashes
origin/masterthe most recent commit on this remote tracking branch
Hashes
Hashes
Navigate with commitish oncommit, status, & log
ArchitectureHash relationships
Hashes
‣Blob‣Tree‣Commit‣Tag
Hashes
treetree: 7e8b1 webblob: 9ab16 index.html
a10b3 treeblob: 8d162 logo.jpgblob: 51d22 draw.js
7e8b1commit
tree: a10b3parent: nilauthor: Firdcommitter: Matthewmessage:
Major refactoringof the web content.
c67db
blob<html>
<body></body></html>
9ab16
blob//Some more javascriptvar renderSize
51d22
blob7D 8D B3 7F BD 12 9F E97B 78 9D 3F 5C A6 72 CB
8d162
Hashes
v1 v2 v3
committree: 9a87bparent: nilauthor: Firdcommitter: Matthewmessage:
Major refactoringof the Javascript renderingengine.
c67db
committree: b22c1parent: c67dbauthor: Timcommitter: Firdmessage:
Minor update to HTML
9bd21
committree: b22c1parent: 9bd21author: Johnnycommitter: Joemessage:
New language transations
1c2d7
Hashes
RELEASE_1.0 HEAD
bug979branch
commitc67db
commit9bd21
commit1c2d7
commit8c2d1
commit1bdcd
commit2daa1
BranchingCreating branches
Branches
default branch name is master
Branches
master doesn’t have any special privileges
Branches
Local Remote Upstream
Branches
# Creating a branchgit branch <BRANCHNAME>
RELEASE_1.0 HEAD
bug979branch
commitc67db
commit9bd21
commit1c2d7
commit8c2d1
commit1bdcd
commit2daa1
Hashes
‣Create a new local branch from HEAD
Branches
# Creating a branchgit branch <BRANCHNAME> HEAD
Branches
# Creating a branchgit branch <BRANCHNAME> <REF>
RELEASE_1.0 HEAD
bug979branch
commitc67db
commit9bd21
commit1c2d7
commit8c2d1
commit1bdcd
commit2daa1
Hashes
‣Create a new local branch from a branch
BranchingBranch as experiments
Branches
What do cheap branches enable?
Branches
‣Experimentation
‣
Branches
‣Experimentation
‣Safe experimentation
Branches
Better reuse of units of work
Hashes
‣Create a branch for an experiment
‣Delete the failed experiment
BranchingBranch frequency
Branches
When should you branch?
Branches
The answer is always
Branches
Branches isolate volatile work
Branches
Branches cost a mere 20 bytes
Branches
We’ve always wanted to branch oftenIt’s just been too expensive, polluting, or ceremonious
Hashes
‣Show branches on the Git project
BranchingBranch lifetimes
Branches
‣Branched by lifetime‣ Product‣ Integration‣ Feature‣ Story‣ Idea
Branches
product
integration
feature
story
idea
product
v1.0 integration
story1 story2
v1.5 integration
story3
Branches
Branches
Local Remote Upstream
Integ
Product
Integ
Product
Integ
Product
Branches
Local Remote Upstream
Idea
Story
Feature FeatureFeature
Integ
Product
Integ
Product
Integ
Product
Branches
Local Remote Upstream
Idea
Story
Feature FeatureFeature
Integ
Product
Integ
Product
Integ
Product
Branches
‣Branch from the master branch
‣Merge from the topic branch
‣Destroy the topic branch
BranchingStashes
Stash
super quick branch
Stash
local-only branch
Stash
‣Numbered branch‣Stack based implementation‣Push, Peek, and Pop operations
(But has direct entry access too)
Stash
creating a stash
Stash
# Stash your pending changesgit stash
Stash
inspecting the stash
Stash
# List your stashesgit stash list
Stash
noting the stash
Stash
# Stash your pending changesgit stash save “<Message>”
Stash
# List your stashesgit stash list
Stash
using the stash
Stash
# Merge & delete the latest stashgit stash pop
Stash
# Merge & delete a stashgit stash pop stash@{0}
Stash
# Merge & keep the latest stashgit stash apply
Branches
‣Stash modified changes
‣Stash staged changes
‣Apply stashed changes
Stash
converting a stash
Stash
# Convert a stash to a branchgit stash branch <newbr>
Stash
# Convert a stash to a branchgit stash branch <newbr> stash@{3}
Branches
‣Convert a stash to a branch
TaggingTag uses
tags as a first class data type
tagging as a cheap operation
New ways to use tags?
Tagging
‣Tagging at each level of approval‣Dev‣CM‣QA‣Production
TaggingTag types
Tagging
reference, annotated and signed tag types
TaggingReference tag
Tagging
reference tag...
Tagging
# Tag HEADgit tag <TAGNAME>
Tagging
# Tag an existing refgit tag <TAGNAME> <REF>
Tagging
# List known tagsgit tag
Tagging
# Show a tag’s contentsgit show tag
Tagging
‣Tag a revision
‣Start a branch from a tag
TaggingAnnotated tag
Tagging
annotated tag...
Tagging
git tag -a <TAGNAME>
Tagging
git show <TAGNAME>
Tagging
‣Tag a revision with an annotated tag
TaggingSigned tag
Tagging
signed tag...
Tagging
git tag -s <TAGNAME>
Tagging
git show <TAGNAME>
Tagging
‣Tag a revision with a signed tag
TaggingTransmitting tags
Tagging
Tags don't push by default
Tagging
# Push all tagsgit push <remote> <tag>
Tagging
# Push all tagsgit push --tags
‣Push a specific tag‣Push all tags
Tagging
Tags do fetch by default
‣Fetch all tags
Tagging
but the refspec doesn’t say to
‣Inspect .git/config refspec
MergingThe basics
Merging
very traditional merge of a branch
Merging
git checkout mastergit merge <featurebranch>
a32
2e2
e69
d19
8b3
Branch
Mas
ter/T
runk
/Mai
nLat
est
Merging
Recursive
Merge
9f1 Mergee698b3
strategy: recursiveresult: no conflicts
a32
e69
d19
Branch
Mas
ter/T
runk
/Mai
nLat
est
Merging
Fast Forward
Merge
Merge
a32
e69
d19
Mas
ter/T
runk
/Mai
nLat
est
Merging
FF
Merge
strategy: recursiveresult: fast forward
a32
2e2
e69
d19
8b3
Branch
Mas
ter/T
runk
/Mai
nLat
est
Merging
Conflicting
Merge
Merge
9f1e698b3
Fix Conflict
strategy: recursiveresult: conflicting
MergingOctopus
Merging
git checkout mastergit merge <fb1> <fb2> <fb3>
strategy: octopus
MergingSubtree
Merging
git checkout mastergit merge -s subtree <fb1>
Merging
git checkout mastergit merge --squash -s subtree <fb1>
strategy: subtree
Tagging
‣Merge a local branch‣Merge a remote branch
RebasingWhat is rebasing?
rebasing is not a merge
Rebasing
rebasing is a preparation for a merge
Rebasing
Merges weave multiple old changes intoa new unifying commit
Rebasing
Rebase reorders the chosen commits before your branch work
Rebasing
simulates team members taking turns working(one person at a time)
Rebasing
RebasingRebasing on a branch
Rebasing
git pull --rebase
Retrieve upstream changes and relocate your local changes to the end
Rebasing
Rebasing
git pull --rebase
# is the same asgit checkout mastergit rebase origin/master
Rebasing
git checkout <featurebranch>git rebase master
a32
2e2
8b3
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
Branch
a32
2e2
8b3
e69
d19
Branch
Mas
ter/
Trun
k/M
ainL
ates
t
Rebase
Rebasing
a32
2e2
e69'
d19'
8b3 Branch
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
Rebase
a32
2e2
e69'
d19'
8b3 Branch
Mas
ter/
Trun
k/M
ainL
ates
t
Merge
Rebasing
Rebasing
‣Rebase topic branch on master
RebasingInteractive rebasing
Rework your work so it makes sense to the team
Rebasing
Rebasing
git checkout myfeaturebranch# Replay the last 5 commitsgit rebase -i HEAD~5
a32
2e2
8b3
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
2e2
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
2e2
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
2e2
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
2e2
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
2e2
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
d19
a32
Mas
ter/
Trun
k/M
ainL
ates
t
Rebasing
e69
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2e2
Rebasing
‣Interactively rebase a single branch
WorkflowsUsage Models
Usage Models
Central Repo
Ce
nt
ra
liz
ed
Usage Models
Blessed Repo
Dic
ta
to
rs
hip
Usage Models
Certified Repo
Development Repo
Int
eg
ra
tio
n M
an
ag
ed
ContinuousIntegration
Server
Usage Models
Cu
st
om
+ P
ub
lic
Co
nt
rib
Customized
� P
riva
te
Pub
lic �
GitHub
Usage Models
Mirror
Development Repo
Mir
ro
re
d
Mirror
Certified Repo
UndoClean
Clean
clean purges untracked files
respects ignored and tracked
Clean
# Dry-run remove filesgit clean -n
Clean
# Dry-run remove files, dirsgit clean -nd
Clean
# Remove filesgit clean -f
Clean
# Remove files, dirsgit clean -fd
Undo
‣Clean untracked files
Clean
# Also remove ignored files
git clean -xf
Clean
# Also remove ignored files, dirs
git clean -xdf
Clean
# Only list ignored files
git clean -Xn
Clean
# Only remove ignored files
git clean -Xf
Undo
‣Clean ignored files
UndoRevert
Revert
revert negates one or more commits
Revert
new commit at the end of HEAD
Revert
no pointer to old ref in revert commit
Revert
comment references the old one
8b3 '
Revert
a32
2e2
d19'
8b3
Revert
a32
2e2
d19'
8b3
Revert
8b3 '
Revert
# Revert a single commitgit revert <ref>
Revert
‣Revert a single change
Revert
# Revert a range of commitsgit revert <ref1>..<ref2>
Revert
# Revert a range of commitsgit revert <old>..<new>
Revert
must have the old..new refs
in the right order
UndoAmend
Amend
amend rewrites the last commit
Amend
git commit --amend
Amend
‣Amend a bad commit message
Amend
git add <missingfile>git commit --amend
Amend
‣Amend a missing file
Git-SVNCloning
git-svn
‣Subversion protocol bridge from Git
‣Round-trip integration
‣Transactions in Git == transactions in SVN
git-svn
# Clone one branchgit svn clone <svnurl>
git-svn
# Clone all branches, tagsgit svn clone --stdlayout <svnurl>
git-svn
‣ Alternate conversion tool‣ svn2git
‣ https://github.com/nirvdrum/svn2git
‣ Converts tags to Git tags
Git-SVNUpdating
git-svn
‣Fetch new changes‣git svn rebase
git-svn
‣Send new changes‣git svn dcommit
Git-SVNSVN Externals
git-svn
‣ SVN Externals
‣ No direct support
‣ Represented as separate repos
‣ Git points at a stable snapshot
‣ SVN Externals follow changes on a branch
git-svn
‣Externals cloning process‣ svn propget svn:externals <MODULE>
‣ git svn clone --stdlayout <THEURL>
‣ git submodule add <THESUBFOLDER>
‣ git submodule init
‣ git submodule update
git-svn
‣ SVN Externals helper script
‣ https://github.com/andrep/git-svn-clone-externals
Git FoundationsAn exploration of the Git toolbox
Offi
cial
trai
ning
cur
ricul
um v
3.1.
0©
201
2, G
itHub
, Inc
.
@matthewmccull
matthew@github.com
github.com/training
Credits
‣ Images sourced from:‣ AmbientIdeasPhotography.com‣ Hand Tools
‣ Flickr Creative Commons‣ Clock: http://www.flickr.com/photos/7729940@N06/4019157830
‣ Wikipedia‣ Linus Torvalds: http://en.wikipedia.org/wiki/File:Linus_Torvalds.jpeg
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