The command line (or terminal) is a faster and more powerful way to maneuver your operating system than by using a GUI (graphical user interface), such as Windows Explorer or Mac Finder.

Use special keywords to do everything you can with a GUI and more.

sed 's/dude/Colt/g' report.txt > report_new.txt

We will use the terminal to:

Option 1: Mac

Option 2: PC

Option 3: Cloud9

There's a

video for that!

There's a

video for that!

There's a

video for that!

🍏

💻

☁️

root /

tmp

Users

Colt

...

Files and directories have absolute paths based on the root, where each additional level down adds a " /".

            /Users/Colt
        

The absolute path for "Colt" is:                   

The green directory below is a special directory called "home", which is also known as "~". This is the default directory upon opening your terminal.

root /

tmp

Users

Colt ~

...

The command "pwd" (print working directory) will tell you the full absolute path of where you're at!

root /

tmp

Users

Colt ~

...

stuff

pwd

/Users/Colt/stuff

The command "cd" ( "change directory") followed by the absolute path of the folder will navigate you directly there.

root /

tmp

Users

Colt ~

...

stuff

pwd

/Users/Colt/stuff

cd /Users

pwd

/Users

The dot "." stands for current directory, and dot-dot ".." stands for parent directory. This allows for relative navigation:

root /

tmp

Users

Colt ~

...

stuff

pwd

cd ..

pwd

/Users/Colt/stuff

/Users/Colt

The keyword "ls" will "list" the contents of a directory. You can supply options such as "-a" to list all files (including hidden ones), or "-l" for a longer format.

total 136
drwxr-xr-x+   42 csteele  staff   1428 Oct  3 10:10 .
drwxr-xr-x     5 root     admin    170 Sep 20 13:10 ..
drwx------     5 csteele  staff    170 Oct  2 10:28 .Trash
-rw-------     1 csteele  staff   7538 Oct  2 10:29 .bash_history
-rw-r--r--     1 csteele  staff    769 Sep 24 17:06 .bash_profile
-rw-------     1 csteele  staff      7 Sep 20 13:51 .python_history
drwx------@    4 csteele  staff    136 Sep 20 13:27 Applications
drwx------+   10 csteele  staff    340 Oct  2 10:37 Desktop
drwx------+    4 csteele  staff    136 Oct  1 10:41 Documents
drwx------+   20 csteele  staff    680 Oct  2 10:08 Downloads
drwx------@   59 csteele  staff   2006 Sep 20 19:44 Library
drwx------+    3 csteele  staff    102 Sep 20 13:10 Movies
drwx------+    3 csteele  staff    102 Sep 20 13:10 Music
drwx------+    3 csteele  staff    102 Sep 20 13:10 Pictures
drwxr-xr-x+    5 csteele  staff    170 Sep 20 13:10 Public
drwxr-xr-x     6 csteele  staff    204 Sep 29 10:53 stuff

ls -la

The command "mkdir" ("make directory") followed by the name of the new directory will create a new child directory inside the current directory.

Colt ~

stuff

The command "touch" followed by the filename and file-type extension will create a new file of that type.

Colt ~

touch favs.txt

stuff

ls

favs.txt

Files can be moved or renamed using the "mv" (" move") keyword, which takes two arguments: the source and the destination.

Colt ~

mv favs.txt GOAT.txt

stuff

ls

GOAT.txt

mv GOAT.txt ../

ls

cd ..

ls

GOAT.txt catpics

Files can be deleted using the "rm" ("remove") keyword.

Colt ~

ls

stuff

GOAT.txt catpics

rm GOAT.txt

ls

catpics

Directories can also be deleted using the "rm" keyword, with the added option "-r" ("recursive"). You can also use "-f" ("force") to prevent warnings.

Colt ~

ls

stuff

catpics

rm -rf catpics

ls

Warning: "rm -rf" is a dangerous command! Be extremely careful what folder you pass to it because you will never get it back.

• OS file structure is hierarchical, tree-based

• Navigate using these commands:
  • cd "change directory"
  • pwd "print working directory"
  • ls "list contents"

• Remember these aliases:
  • / is root directory
  • ~ is home
  • . is current
  • .. is parent

• Manipulate files with:
  • "mkdir" create directories
  • "touch" create files
  • "mv" move and rename
  • "rm" to remove files, "-r" to remove directories

Git is the most popular "version control system" - a tool to keep track of file changes over time. 

It allows you connect your code to online repositories to back up everything easily.

It also makes collaborating with other people on code projects more manageable through branches.

GitHub is an online service that hosts git repositories for developers.

It's also a major platform for collaboration on both private enterprise and open source projects

GitHub repositories keep track of entire code history online, so you get both the current state of files and also all previous versions.

1a. Initialize a local repository on your computer

2. Change (create, edit, move, remove) files on your computer

3. Stage the files to be committed

4. Commit the files to a new version

5. Push changes to the online repository

1b. Clone (download) an online repository onto your computer

or

Once git is installed, any directory on your computer can be turned into a repository by typing "git init" inside the folder.

This command creates a "hidden" .git folder in the directory which is where your versions are stored.

Initialized empty Git repository in /Users/Colt/test/.git

One you have created some files in your repository, you can add them to the stage by typing "git add" followed by the filename or parent directory of the files to add all of them.

monty.py

git add .

monty.py

Stage

Changes in local git repository

Staging a file takes a snapshot of it at a point in time, which will prepare it for a new commit (the next version of the repo).

Use the command "git commit" to save a new version of the repository. Use the "-m" (message) argument followed by a short description to explain the new version.

git commit -m "added monty python"

.git directory

The new commit stores the snapshot in the .git folder. Every commit gets indexed with an auto-generated unique hash so git can find it easily later.

a84c25deac4a8b7c899c34694b569d88349d5a8b "added monty python"

So far, all of the changes we're making are affecting our local .git folder only. Our changes are thus only on our machine.

We can add a remote origin by making a GitHub repository and typing the command "git remote add origin" like so:

git remote add origin https://github.com/<your_github_handle>/<your_repo_name>.git

After you've set up a remote origin, use the command "git push" to publish your changes to your online GitHub repository.

Pushing synchronizes the local and remote repositories. Sometimes you will have to "git pull" first to bring your local repo up-to-date before pushing.

Repository on GitHub

            a84c25deac4a8b7c899c34694b569d88349d5a8b "added monty python"
        

git push origin master
        

1a. Initialize a local repository on your computer

2. Change (create, edit, move, remove) files on your computer

3. Stage the files to be committed

4. Commit the files to a new version

5. Push changes to the online repository

1b. Clone (download) an online repository onto your computer

or

git init

git clone https://github.com/<your_github_handle>/<your_repo>.git

echo "just putting text in this file" >> README.md

git add .

git commit -m "my first commit"

git push origin master