Differences

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--- git [2026/06/15 01:57] – [log] jhagstrand
+++ git [2026/08/06 07:54] (current) – [repository] jhagstrand
@@ Line 52: / Line 52: @@
 === bare===
 a bare repository is a folder named project.git\\
-a non-bare repository is a subfolder named .git, co-residing in the project folder along with the working copy\\
+a non-bare repository is a sub-folder named .git, co-residing in the project folder along with the working copy\\
-  git init
+  git init  # executed from within a new project folder, creates the .git folder
-  git clone
+  git init --bare flash.git  # create a new sub-folder named flash.git
+  git clone <server.path>.flash.git # create sub-folder named flash, within which lies the .git sub-folder
 ====remote====
@@ Line 268: / Line 270: @@
 | git checkout <commit>  | (none)   |
-The old checkout commands still work as always.  And kudos to the git developers for honoring backward compatibility.
+The old checkout command still works the same as always.
+**git checkout <branch>**
+This allows developers to work on multiple ideas at once, and switch back and forth.
+**git checkout <file>**
+When you change your mind about the changes you've made, restore the file back to where it was before you started.
+**git checkout <commit>**
+When I'm testing my app and I'm not sure if my latest commit was successful,
+I can temporarily switch back to the previous commit and test that to refresh my memory.
+Note that this results in a "detached HEAD".
+The HEAD is a pointer to a commit.
+Anytime the HEAD is pointed at a commit other than the one at the top of the current branch, it is considered detached.
+Repeat the git checkout <branch> to implicitly reattach the HEAD.
+==== checkout ====
+The repo is a library of commits.
+At any time, you can checkout a whole commit or a specific file within that commit.
+A branch is a pointer to a commit.
+The HEAD is also a pointer to a commit.
+When the HEAD points to a commit that is not also the top of a branch, the HEAD is considered "detached".
+The checkout command does two things:
+. Points the HEAD to the specified commit.
+. Brings the working tree into line with the new HEAD commit.
+You can specify a commit, a branch, or a file.
+  git checkout <branch>
+  git checkout <commit>
+  git checkout <file>
+You can specify a branch or a commit; either way you are specifying a commit.
+If you specify a file, there is no need to move the HEAD.  It just modifies that one file in the working tree to bring it into line with the current commit.
+Younger developers who don't yet fully understand the checkout command, in 2019, introduced two new aliases.
+^ correct                ^ alias               ^
+| git checkout <branch>  | git switch <branch>  |
+| git checkout <file>    | git restore <file>   |
-(Note that checkout of a commit is extraordinary and results in a detached HEAD.)
 ====diff====
-Use diff to find the differences between two branches or between two files.\\
+Use diff to find the differences between two commits.\\
-Note that there is a big difference between .. and ... between the two commit designations.\\
-Also the two hyphens -- can go before or after the filename and that alters the output.\\
-  git diff master...featurebranch  # compare two branches
+  git diff 1bde095 b0ba90d   # compare two commits
+  git diff master sidebar    # compare two branches
-  git diff 1bde095..b0ba90d -- html/js/hud.js  # compare two different commits of a file
+  git diff master sidebar hud.js  # compare two versions of a file
 By default diff compares all of the currently modified files.
-  git diff         # before the add
+  git diff           # before staging
-  git add .
+  git add .          # staging
-  git diff HEAD    # after the add
+  git diff HEAD      # after staging
+  git diff --staged  # after staging
 Additional options.
+  git diff master sidebar --stat   # show filenames and counts only
   git diff -U0	# do not display context
-  git diff -w	# ignore whitespace
-  git diff -w --word-diff-regex=[^[:space:]]	# ignore whitespace additional
+Whitespace.\\
 In .gitconfig, add
 [core] whitespace = -trailing-space,-indent-with-non-tab,-tab-in-indent
+  git diff -w	# ignore whitespace
+  git diff -w --word-diff-regex=[^[:space:]]	# ignore whitespace additional
+Dots.\\
+If both master and sidebar have changed, and you want to see only differences in sidebar, use three dots.  (This is a shortcut to naming the commit specifically.)\\
+Warning! Two dots vs three dots makes a difference, and the difference is reversed in git diff vs git log.\\
+  git diff master sidebar poker.js  # compare changes from latest master to latest sidebar
+  git diff master..sidebar poker.js  # same as no dots
+  git diff master...sidebar poker.js  # not latest master but master when sidebar branched
+Double hyphens.\\
+I don't know why this is used.\\
+  git diff master sidebar hud.js
+  git diff master sidebar -- hud.js
+  git diff master sidebar hud.js --
 ====log====
@@ Line 305: / Line 370: @@
   git log --all --oneline --graph --decorate  # all branches, graph hierarchy
   git log --oneline -10     # topmost n lines
+  git log --all --pretty=fuller
 ==== interactive rebase ====
@@ Line 321: / Line 386: @@
 https://www.sitepoint.com/git-interactive-rebase-guide/
+==== Combinations ====
+Some git command options effectively execute multiple git commands simultaneously.
+Here are some examples.
+. git add .
+. git commit -m 'latest fix'
++2. git -a commit -m 'latest fix'      # combine add and commit
+. git clone <project>
+. git submodule init
+. git submodule update
++3. git submodule update --init
++2+3. git clone --recursive-submodules <project>
+. git fetch     # download patch files
+. git merge     # apply patches to local files
++2. git pull    # fetch and merge
+====Fork====
+In github ui, fork repo from voyc to hagstrand.  A fork is a server-side clone.
+Locally:
+	git clone xttps://github.com/hagstrand/flash flashbang   # specified target <directory>
+	git remote add upstream xttps:github.com/voyc/flash   # second remote
+	git pull --rebase upstream master   # pull changes from upstream, update local, no commit
+	# pull does a fetch and merge into local directory.  No need to commit.
+	git push origin master
+	Todo: Rename?
+	Todo: In github UI, “Pull Request” to bring forked project back into upstream.
 ===== How to use =====
@@ Line 602: / Line 700: @@
 	git submodule update --init   # copies entries from .gitmodules to .git/config, and pulls each
-==== Combinations ====
-Some git command options effectively execute multiple git commands simultaneously.
-Here are some examples.
-. git add .
+==== Remove a submodule ====
-. git commit -m 'latest fix'
-+2. git -a commit -m 'latest fix'      # combine add and commit
-. git clone <project>
+Remove a submodule but keep the working tree.
-. git submodule init
+<code>
-. git submodule update
+# 1. Remove the submodule entry from .gitmodules
-+3. git submodule update --init
+git submodule deinit -f path/to/submodule
-+2+3. git clone --recursive-submodules <project>
-. git fetch     # download patch files
+# 2. Remove it from git's index and the .git/modules cache
-. git merge     # apply patches to local files
+git rm -f path/to/submodule
-+2. git pull    # fetch and merge
+rm -rf .git/modules/path/to/submodule
-====Fork====
+# 3. Commit the removal
-In github ui, fork repo from voyc to hagstrand.  A fork is a server-side clone.
+git commit -m "Remove submodule path/to/submodule, keep files as plain code"
-Locally:
-	git clone xttps://github.com/hagstrand/flash flashbang   # specified target <directory>
-	git remote add upstream xttps:github.com/voyc/flash   # second remote
-	git pull --rebase upstream master   # pull changes from upstream, update local, no commit
-	# pull does a fetch and merge into local directory.  No need to commit.
-	git push origin master
-	Todo: Rename?
-	Todo: In github UI, “Pull Request” to bring forked project back into upstream.
-====See the current changes====
+# 4. Re-add the files as normal tracked files
-	git diff  # before staging (git add *)
+git add path/to/submodule
-	git diff --staged # after staging
+git commit -m "Add formerly-submoduled files as plain code"
+</code>
 =====Alternative Workflows=====