GitHub/school-of-sre
1
0
Fork 0
mirror of https://github.com/linkedin/school-of-sre synced 2026-01-16 21:48:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

Remove shell prompt so shell commands are easier to read

Browse Source 
This fixes this issue #83
I made this commit by running a find replace with the pattern
'^.*spatel1\$'
and replaced it with
'$'
This commit is contained in:
Opemipo Ogunkola
2021-01-06 14:51:11 +00:00
committed by Sanket Patel
parent 6100c9af50
commit a605e72695
5 changed files with 71 additions and 71 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
courses/git/git-basics.md
View File

@@ -33,19 +33,19 @@ Any folder can be converted into a git repository. After executing the following
```bash
# creating an empty folder and changing current dir to it
spatel1-mn1:~ spatel1$ cd /tmp
spatel1-mn1:tmp spatel1$ mkdir school-of-sre
spatel1-mn1:tmp spatel1$ cd school-of-sre/
$ cd /tmp
$ mkdir school-of-sre
$ cd school-of-sre/
# initialize a git repo
spatel1-mn1:school-of-sre spatel1$ git init
$ git init
Initialized empty Git repository in /private/tmp/school-of-sre/.git/
```
As the output says, an empty git repo has been initialized in our folder. Let's take a look at what is there.
```bash
spatel1-mn1:school-of-sre spatel1$ ls .git/
$ ls .git/
HEAD config description hooks info objects refs
```
@@ -56,8 +56,8 @@ There are a bunch of folders and files in the `.git` folder. As I said, all thes
Now as you might already know, let us create a new file in our repo (we will refer to the folder as _repo_ now.) And see git status
```bash
spatel1-mn1:school-of-sre spatel1$ echo "I am file 1" > file1.txt
spatel1-mn1:school-of-sre spatel1$ git status
$ echo "I am file 1" > file1.txt
$ git status
On branch master
No commits yet
@@ -73,8 +73,8 @@ nothing added to commit but untracked files present (use "git add" to track)
The current git status says `No commits yet` and there is one untracked file. Since we just created the file, git is not tracking that file. We explicitly need to ask git to track files and folders. (also checkout [gitignore](https://git-scm.com/docs/gitignore)) And how we do that is via `git add` command as suggested in the above output. Then we go ahead and create a commit.
```bash
spatel1-mn1:school-of-sre spatel1$ git add file1.txt
spatel1-mn1:school-of-sre spatel1$ git status
$ git add file1.txt
$ git status
On branch master
No commits yet
@@ -84,7 +84,7 @@ Changes to be committed:
new file: file1.txt
spatel1-mn1:school-of-sre spatel1$ git commit -m "adding file 1"
$ git commit -m "adding file 1"
[master (root-commit) df2fb7a] adding file 1
1 file changed, 1 insertion(+)
create mode 100644 file1.txt
@@ -101,9 +101,9 @@ Commit is a snapshot of the repo. Whenever a commit is made, a snapshot of the c
Let us create one more file and commit the change. It would look the same as the previous commit we made.
```bash
spatel1-mn1:school-of-sre spatel1$ echo "I am file 2" > file2.txt
spatel1-mn1:school-of-sre spatel1$ git add file2.txt
spatel1-mn1:school-of-sre spatel1$ git commit -m "adding file 2"
$ echo "I am file 2" > file2.txt
$ git add file2.txt
$ git commit -m "adding file 2"
[master 7f3b00e] adding file 2
1 file changed, 1 insertion(+)
create mode 100644 file2.txt
@@ -116,7 +116,7 @@ A new commit with ID `7f3b00e` has been created. You can issue `git status` at a
Now that we have two commits, let's visualize them:
```bash
spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
$ git log --oneline --graph
* 7f3b00e (HEAD -> master) adding file 2
* df2fb7a adding file 1
```
@@ -134,7 +134,7 @@ spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
As I just said, the two commits we just made are linked via tree like data structure and we saw how they are linked. But let's actually verify it. Everything in git is an object. Newly created files are stored as an object. Changes to file are stored as an objects and even commits are objects. To view contents of an object we can use the following command with the object's ID. We will take a look at the contents of the second commit
```bash
spatel1-mn1:school-of-sre spatel1$ git cat-file -p 7f3b00e
$ git cat-file -p 7f3b00e
tree ebf3af44d253e5328340026e45a9fa9ae3ea1982
parent df2fb7a61f5d40c1191e0fdeb0fc5d6e7969685a
author Sanket Patel <spatel1@linkedin.com> 1603273316 -0700
@@ -146,7 +146,7 @@ adding file 2
Take a note of `parent` attribute in the above output. It points to the commit id of the first commit we made. So this proves that they are linked! Additionally you can see the second commit's message in this object. As I said all this magic is enabled by `.git` folder and the object to which we are looking at also is in that folder.
```bash
spatel1-mn1:school-of-sre spatel1$ ls .git/objects/7f/3b00eaa957815884198e2fdfec29361108d6a9
$ ls .git/objects/7f/3b00eaa957815884198e2fdfec29361108d6a9
.git/objects/7f/3b00eaa957815884198e2fdfec29361108d6a9
```
@@ -158,11 +158,11 @@ We already can see two commits (versions) in our git log. One thing a version co
```bash
# Current contents, two files present
patel1-mn1:school-of-sre spatel1$ ls
$ ls
file1.txt file2.txt
# checking out to (an older) commit
spatel1-mn1:school-of-sre spatel1$ git checkout df2fb7a
$ git checkout df2fb7a
Note: checking out 'df2fb7a'.
You are in 'detached HEAD' state. You can look around, make experimental
@@ -177,7 +177,7 @@ do so (now or later) by using -b with the checkout command again. Example:
HEAD is now at df2fb7a adding file 1
# checking contents, can verify it has old contents
spatel1-mn1:school-of-sre spatel1$ ls
$ ls
file1.txt
```
@@ -190,12 +190,12 @@ I mention in the previous section that we need a _reference_ to the version. By
Similarly, master is also a reference (to a branch). Since git uses tree like structure to store commits, there of course will be branches. And the default branch is called `master`. Master (or any branch reference) will point to the latest commit in the branch. Even though we have checked out to the previous commit in out repo, `master` still points to the latest commit. And we can get back to the latest version by checkout at `master` reference
```bash
spatel1-mn1:school-of-sre spatel1$ git checkout master
$ git checkout master
Previous HEAD position was df2fb7a adding file 1
Switched to branch 'master'
# now we will see latest code, with two files
spatel1-mn1:school-of-sre spatel1$ ls
$ ls
file1.txt file2.txt
```
@@ -206,7 +206,7 @@ Note, instead of `master` in above command, we could have used commit's ID as we
Let's look at the state of things. Two commits, `master` and `HEAD` references are pointing to the latest commit
```bash
spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
$ git log --oneline --graph
* 7f3b00e (HEAD -> master) adding file 2
* df2fb7a adding file 1
```
@@ -214,7 +214,7 @@ spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
The magic? Let's examine these files:
```bash
spatel1-mn1:school-of-sre spatel1$ cat .git/refs/heads/master
$ cat .git/refs/heads/master
7f3b00eaa957815884198e2fdfec29361108d6a9
```
@@ -223,7 +223,7 @@ Viola! Where master is pointing to is stored in a file. **Whenever git needs to
Similary, for `HEAD` reference:
```bash
spatel1-mn1:school-of-sre spatel1$ cat .git/HEAD
$ cat .git/HEAD
ref: refs/heads/master
```
@@ -234,7 +234,7 @@ We can see `HEAD` is pointing to a reference called `refs/heads/master`. So `HEA
We discussed how git will update the files as we execute commands. But let's try to do it ourselves, by hand, and see what happens.
```bash
spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
$ git log --oneline --graph
* 7f3b00e (HEAD -> master) adding file 2
* df2fb7a adding file 1
```
@@ -242,13 +242,13 @@ spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
Now let's change master to point to the previous/first commit.
```bash
spatel1-mn1:school-of-sre spatel1$ echo df2fb7a61f5d40c1191e0fdeb0fc5d6e7969685a > .git/refs/heads/master
spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
$ echo df2fb7a61f5d40c1191e0fdeb0fc5d6e7969685a > .git/refs/heads/master
$ git log --oneline --graph
* df2fb7a (HEAD -> master) adding file 1
# RESETTING TO ORIGINAL
spatel1-mn1:school-of-sre spatel1$ echo 7f3b00eaa957815884198e2fdfec29361108d6a9 > .git/refs/heads/master
spatel1-mn1:school-of-sre spatel1$ git log --oneline --graph
$ echo 7f3b00eaa957815884198e2fdfec29361108d6a9 > .git/refs/heads/master
$ git log --oneline --graph
* 7f3b00e (HEAD -> master) adding file 2
* df2fb7a adding file 1
```