mirror of https://github.com/tildeclub/site.git
add beginner cli guide
This commit is contained in:
Ben Harris
parent
8b7f95ae74
commit
844aa0bbb1
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@ -10,6 +10,7 @@ all: $(DST_HTML_FILES)
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--template wiki.tmpl \
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--lua-filter header-permalinks.lua \
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--title-prefix "tilde.club wiki" \
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--variable toc-title:"table of contents" \
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--standalone \
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--table-of-contents \
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--output $@ \
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@ -0,0 +1,514 @@
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---
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title: command line for absolute beginners
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author: cmccabe
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---
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So, you want to join a public-access shell community like tilde.club,
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but you don't yet have experience using GNU+Linux or other UNIX-like
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operating systems? This tutorial is designed to give you enough guidance
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that you can get started and move on to successfully directing your
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future learning. Once you get a basic level of self-sufficiency,
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tilde.club is a great place to practice and learn more.
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GNU+Linux is a text-based operating system. And it takes work and thought to start using.
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-----------------------------------------------------------------------------------------
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You'll find a lot of people online arguing that GNU+Linux is *not* a
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text-based operating system, and that it in fact has a GUI interface
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just like Windows. It is true that you can use GNU+Linux through a
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graphical user interface (GUI) like Gnome, or that you can use services
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from GNU+Linux servers like tilde.club through a web interface. But the
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people who are so keen on GUIs are saying this to make GNU+Linux sound
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like an easy transition for Windows or Mac users. However: (1) to really
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leverage the power of GNU+Linux, you need to learn to interact with it
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as a text-based system, and (2) while it is different, it's not really
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that hard. It will take effort to learn the differences, but that effort
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will pay huge dividends.
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How do I connect to a shell server?
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-----------------------------------
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The most common way to connect remote GNU+Linux system is with an SSH
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client. SSH stands for secure-shell. SSH allows you to make a private
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connection between your computer and a shell server like
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[tilde.club](https://tilde.club), and it ensures that nobody else along
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the wire can listen in on your connection. Check out [our SSH
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page](/wiki/ssh.html) for information on connecting to tilde.club over
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SSH.
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If you are having trouble with making your first SSH connection to
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tilde.club, or anything else while you're learning from this tutorial,
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drop by the [tilde.club web chat](https://web.tilde.chat/) or email an
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admin for help (<root@tilde.club>).
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What is a shell?
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----------------
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An operating system (OS) is the nuts and bolts that makes all the parts
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of your computer work together for you. At its core, the OS is not
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friendly for day to day computer usage. A shell is a user friendly
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"wrapper" around the operating system that allows you to use it easily.
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A shell can be graphical, like the Windows or Android GUIs. Or a shell
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can be text-based. A text based shell, also called a command line
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interface (or CLI), is a tool you can use to control the operating
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system by sending it text commands.
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What kind of things can you make the OS do? Things like opening files,
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listing the files in a directory, displaying the current system load, or
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telling you what other users are currently doing.
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What is a command?
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------------------
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Commands are simple words, often abbreviated, that make the system do
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things when typed into the shell. Some simple examples are 'ls' which
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lists the files in a directory, or 'cd' which changes your location to a
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new directory (cd = change directory), or 'exit' which logs you out of
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your current shell session. There are thousands of useful commands, but
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you only need to know a few to get started and be self-sustaining.
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This tutorial will teach you the few commands that should allow you to
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take care of yourself and start down the real, longer-term path of
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self-directed learning. Once you're logged into tilde.club (or any
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GNU+Linux shell server), you can practice the following commands as you
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learn them.
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What are the first commands a new user should learn?
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----------------------------------------------------
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When you're first starting to use a shell in a UNIX-like environment,
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you will want to be able to do the following things:
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1. logging in and logging out
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2. list the files or directories in a directory
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3. move between directories
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4. read, write, and save files
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5. create new files or directories
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6. move or copy files between directories
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7. delete files or directories
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8. download files from elsewhere on the internet
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9. learn more about new commands
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When you're logged into a shell, you should see a command prompt and a
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blinking cursor. At this point, simply type a command and hit Enter to
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run it. You can try this as you work through learning the commands
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below.
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### Logging In, with `ssh`
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Recall from the How-Do-I-Connect section above that you can use a SSH
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client to log into tilde.club. Once you're logged in, you can use the
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command line SSH client to log into any other shell server; in the
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example below, let's say you want to log into tilde.town from
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tilde.club.
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Skipping some specifics for now, you can log into tilde.town from a
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tilde.club shell by using SSH as follows:
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> `ssh username@tilde.club`
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Some shell servers allow you to log in with nothing more than a username
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and password. But increasingly, many servers (like both tilde.club and
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tilde.town) require you to use ssh keys. To learn more about ssh keys,
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again, see our [SSH page](/wiki/ssh.html).
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### Logging Out, with `logout` or `exit`
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`logout` is a simple command you can use to log out of a shell. You
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could also use `exit`.
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### Listing Files, with `ls`
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To list the files in a directory, simply type `ls`. This will print a
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list of the files in your current directory.
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> `ls`
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### Changing Directories, with `cd`
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You may move from one directory to another with `cd`. Wherever you are
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in the file system, you can type `cd` by itself to return to your home
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directory:
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> `cd`
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Change to the directory with your html files as follows:
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> `cd public_html`
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### Read the Contents of a File, with `less`
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If you're still in your public\_html directory, you should see a file
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called 'index.php' when you use the `ls` command. Let's peek inside
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'index.php' as follows:
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> `less index.php`
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`less` has opened the 'index.php' file for you to read. You cannot edit
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it; only read it. Type `q` (quit) to stop viewing the file contents and
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return to the shell.
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### Edit and Save Changes to a File, with `nano`
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`nano` is one of many text editors availble for GNU+Linux. There are
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many more powerful editors, but we'll start with this one because it is
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simple. Let's open your 'index.php' file and make some changes.
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> `nano index.php`
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Now you're viewing the contents of 'index.php' again, but this time you
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can change the contents. If you don't know HTML, be careful here. Use
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your arrow keys to move the cursor down to the line that says the
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following:
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`<p>Just log in with your secure internet shell to change this file!</p>`
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Leave the `<p>` and `</p>` tags as they are, but change the sentence in
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between them.
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Now, save and quit by hitting the key combination Ctrl+x, and then
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typing 'y' in response to the question about wanting to save the
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modified buffer.
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Now you can pull up a browser to see the change at your tilde.club URL:
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'https://tilde.club/\~yourUserName'
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### Create a New File with `nano`
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Let's create a new file in your public\_html directory, called
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'testing.html'.
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> `nano testing.html`
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'testing.html' did not exist before you opened it with `nano`, so it was
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created for you.
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Now, add some quick contents by opening the file for editing with
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`nano`, and adding whatever you want. Then Ctrl+x to save, you will have
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created a new file.
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Type `ls` to view the contents of your directory an confirm that you did
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indeed make the file.
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Later in this tutorial, we will come back to this file and make it
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viewable in your web space.
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### Create a New Directory, with `mkdir`
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First, hop back to your home directory with the `cd` command (remember
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that `cd` from anywhere in the file system will take you back to your
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home directory).
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Now create a new directory called 'downloads' in your home directory:
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> `mkdir downloads`
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Use `ls` to see that it was created, and even move into the new
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directory with `cd downloads`.
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### Moving Files Between Directories, with `mv` or `cp`
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First, `cd` back to your home directory, and use `nano` to create two
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new files called 'fileone.txt' and 'filetwo.txt'.
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Lets move those into your 'downloads' directory using two different
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commands, to demonstrate how they workd differently.
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Move 'fileone.txt' into 'downloads':
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> `mv fileone.txt downloads/`
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Now if you `ls` the contents of your home directory, you will no longer
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see 'fileone.txt', because it has been moved into 'downloads'. If you
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'ls' the contents of 'downloads' (a shortcut command is `ls downloads`),
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you will see it there.
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Next, copy 'filetwo.txt' into 'downloads' as follows:
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> `cp filetwo.txt downloads`
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Now if you `ls` the contents of your home directory, 'filetwo.txt' will
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still be there. This is because `cp` made a copy of 'filetwo.txt' and
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put the copy in 'downloads'. It did not touch the original file in your
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home directory. Verify this with `ls` in your home directory and in
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'downloads'.
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### Delete Files and Directories, with `rm` and `rmdir`
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As long as you're in one of your own directories (e.g. your home, or
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'downloads' or 'public\_html'), you can create a new files. Create a new
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file called 'testtrash.txt':
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> `nano testtrash.txt`
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Then save it as you have already learned, and confirm that it exists by
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listing (`ls`) the contents of the directory.
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Now, you can delete the file with the `rm` (remove) command:
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> `rm testtrash.txt`
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Notice that you don't get a warning that you're about to delete it, and
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you don't even get a confirmation that it is deleted. You've learned
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your first command that you need to be careful with. If you delete an
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important file with `rm`, it is gone forever.
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You can delete directories the same way, only using the `rmdir` command
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(remove directory) instead of `rm`. If you use `mkdir testtrash`, you
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can then delete it as follows:
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> `rmdir testtrash`
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Note that you can only delete empty directories with `rmdir`.
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If you want to delete directories that still have contents in them, use
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the following:
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> `rm -rf directoryName`
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Be very, very careful with this command. Many a user, new and seasoned,
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has been stung by hastily deleting directories like this. This is also
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the source of the classic sysadmin joke/horror story about `rm -rf /`
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which deletes the entire file system.
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### Downloading Files, with `wget`
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Now `cd` into your 'downloads' directory because we're going to use it
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for actual downloads.
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Use the `wget` (WWW get) command to download a text copy of this
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tutorial from tilde.club user cmccabe's public\_html directory:
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> `wget https://tilde.team/~cmccabe/gnu-linux-toot.txt`
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You will see output of the command that confirms it is downloading. You
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can also verify that it has downloaded with your `ls` command. You can
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also peek at the contents with the `nano` or `less` commands that you
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learned above.
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If you know the URL of other files you'd like to download, you can grab
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those too, just swapping the URL above for any URL:
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> `wget [URL here]`
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A brief note on security here, if you do pull any scripts from the
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Internet using `wget`, it's important that you do not execute those
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scripts until you've read over what it does. Otherwise, you run the risk
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of compromising your account or allowing other malicious actions to take
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place.
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### Learn More About Commands, with `man` (and `help`)
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At this point, you've learned most of the commands you need for basic
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self-sufficiency in a GNU+Linux shell environment. With just a few more,
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you can go a long way. When you want to learn more about a command, you
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can look at its "man page" with the `man` command. "Man pages" are the
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instruction manuals for most commands and programs in GNU+Linux.
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Try out `man` by looking at any of the commands you've learned already
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(except `cd`\*). For example, `man ls` would open the man page for the
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`ls` command. When looking at a man page, type `q` at any time to quit
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and return to the shell.
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The `man` command will be one of your most valuable tools for as long as
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you're using the GNU+Linux shell. You will always be learning new
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commands and new ways to use old commands, and `man` will help you do
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it.
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\* Note: technically speaking `cd` is a shell built-in, not a command.
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Make a mental note of that and you can learn more about the distinction
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later. For now, note that you can use `help cd` to learn more about the
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`cd` command.
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Commands have options and arguments.
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------------------------------------
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When you look at the man page for a command like `ls`, you'll see in the
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DESCRIPTION section a number of **options** that you can use to modify
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how the command works. They look like `-a` or `-h` or `-l`. Try adding
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the `-a` option to `ls` and note the difference:
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> `ls -a`
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The `-a` option now lists "all" contents of your directory, including
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"hidden" files (aka dot files). You could combine the three options
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listed above in the form of `ls -alh` to list "all" files, in "long"
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form, and display file sizes in "human" readable format. Most commands
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have
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Commands also have **arguments**, or information passed into a command
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for some kind of processing. You have already used these arguments when
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you told nano to open a file: `nano testtrash.txt`. In this case,
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"testtrash.txt" was the argument to the nano command. You also used
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"testtrash.txt" as an argument to the `rm` command when you did
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`rm testtrash.txt`.
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Commands will often combine options and arguments, sometimes in specific
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sequences. You can learn about these when read a command's man page.
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The Filesystem Hierarchy
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------------------------
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You already know that you get dropped into your "home" directory when
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you first log in. Your home directory is just one of many, many other
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directories on the system. All of these directories are organized under
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one master directory called the "root directory". The root directory is
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often referred to with a single forward slash, like this: /
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You can list all the directories at the root level by using the `ls`
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command again, as follows:
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> `ls /`
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Want to check out some of the directories you see in root? You could
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either `cd` into them and `ls` the contents, or just `ls` the comments
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directly as follows:
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> `ls /etc`
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This would display the contents of the "etc" directory, which itself
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lives in the "root" directory. Notice that the command uses "/" + "etc"
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to create a path to the destination. In "etc" is another directory
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called "cron.d", and you can use the same principle to view its
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contents:
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> `ls /etc/cron.d`
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You now know enough to look around the file system. Note that most
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GNU+Linux systems (like tilde.club) adhere somewhat to an organization
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scheme called the Filesystem Hierarchy Standard ([Wikipedia
|
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link](https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard)).
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This is another subject for you to read up on later.
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How can I keep my things private, or share them with others?
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------------------------------------------------------------
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As you explore the filesystem, you might bump into some directories that
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won't let you in. For example, if you try to `cd` into the home
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directory for the root user (not the same as the root directory), you'll
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see this error: "/root: Permission denied". This is because GNU+Linux
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systems maintain a "mode" for each file that limits which users can
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read, write or execute it.
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If you don't own a file, then you can't change its mode. This is a basic
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security principle in GNU+Linux systems.
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For the files you own (i.e. the files within your home directory), you
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can change the file modes yourself. You do this using the "change mode"
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command, `chmod`.
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Each file has three permission levels: for the file owner, for members
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of the file's group\*, and for all other system users. For each level,
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you can permit any combination of "read", "write", and "execute"
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permissions.
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(/\* Do a web search for GNU+Linux users and groups to learn more about
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this important concept.)
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You can change a file's mode with `chmod` one of two ways. The first is
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a symbolic way in which you add or subtract 'r', 'w', and/or 'x' (read,
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write, execute) to 'u', 'g', or 'o' (user, group, or other). For
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example:
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> `chmod g+x filename.txt`
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This gives 'execute' privileges to members of filename.txt's group.
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You can also use `chmod` numerically, through which you may set the
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user, group and other permissions all at once. For example:
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> `chmod 755 filename.txt`
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This gives the owner read, write and execute privileges, and gives only
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read and execute privileges to group and other.
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Use `man chmod` to get a fuller understanding of `chmod`.
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To get an interactive, visual feel for numeric file modes, try the
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cmccabe's [file mode widget](https://tilde.team/~cmccabe/mode-gui.php)
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|
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--
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Finally, remember that 'testing.html' file we made above? Let's use that
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as an example of how you can control who can view your files. Use the
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following to make the 'testing.html' file visible in your website:
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> `cd` to return to your home directory
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> `chmod 644 public_html testing.html`
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Now if you bring up the following URL (with your username) in a browser,
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you should see the testing.html file you made.
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https://tilde.club/\~username/testing.html
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The End (of The Beginning)
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||||
--------------------------
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There you have it -- you know about logging in, using basic shell
|
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commands, and the file system, and you're now self-sustaining (and a
|
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little more).
|
||||
|
||||
tilde.club is about community, but it is about community of individuals
|
||||
who work hard to learn. what you have just leaned will give you a
|
||||
platform on which you can learn by doing and trying things out.
|
||||
|
||||
Remember that - There is NO GUILT here. NOR SHAME. Not knowing things is
|
||||
fine. Feel free to ask your questions any time on irc or the mailing
|
||||
list.
|
||||
|
||||
Below are some other common programs you'll likely want to use. Most of
|
||||
these have man pages, so you can read more about them. Others you'll
|
||||
just have to try out to see how they work.
|
||||
|
||||
List of Common Programs
|
||||
-----------------------
|
||||
|
||||
`mutt`, `alpine` - for email
|
||||
|
||||
`wget`, `curl` - for grabbing files from elsewhere
|
||||
|
||||
`weechat`, `irssi` - for irc
|
||||
|
||||
`scp` - for securely moving files between networked systems. this copies
|
||||
files (i.e. 'cp') over ssh, hence 'scp'
|
||||
|
||||
`lynx` - web browsing
|
||||
|
||||
`crontab` - scheduling recurring jobs (job = sequence of commands, often
|
||||
stored in a script)
|
||||
|
||||
`dict` - dictionary for definitions and synonyms
|
||||
|
||||
`aspell` - a program for spell checking
|
||||
|
||||
`motd` - list the message of the day, which on tilde.club displays all
|
||||
the other commands below
|
||||
|
||||
some tilde.club specific programs
|
||||
---------------------------------
|
||||
|
||||
`bbj` - a bulletin board for asynchronous discussions
|
||||
|
||||
`botany` - tend to your plants and help others care for theirs
|
||||
|
||||
`asciifarm` - a lovely multiplayer, text-based, farming RPG
|
||||
|
||||
`tilde` - a manager for user-submitted scripts
|
||||
|
||||
`chat` - open `weechat` preconnected to our irc
|
||||
|
||||
Some shell use cases
|
||||
--------------------
|
||||
|
||||
And in this corner, we shall describe some common activities people
|
||||
perform in a shell... \[Feel free to add here.\]
|
||||
|
||||
Other Intro-to-Linux Material
|
||||
-----------------------------
|
||||
|
||||
Not suprisingly, you'll find a lot of other intro material online or in
|
||||
your local library. Here are a few that have been mentioned by
|
||||
tilde.club members:
|
||||
|
||||
Terminus - an interactive game-like introduction to shell commands
|
||||
http://www.mprat.org/Terminus/
|
||||
|
|
@ -68,9 +68,13 @@ $highlighting-css$
|
|||
</header>
|
||||
$endif$
|
||||
$if(toc)$
|
||||
$if(toc-title)$
|
||||
<h2>$toc-title$</h2>
|
||||
$endif$
|
||||
<nav id="$idprefix$TOC">
|
||||
$table-of-contents$
|
||||
</nav>
|
||||
<hr>
|
||||
$endif$
|
||||
$body$
|
||||
$for(include-after)$
|
||||
|
|
|
|||
Loading…
Reference in New Issue