Linux Command Line: Basic Commands
In this tutorial series, we'll see how to use the Linux Command Line.
Download and print out the Cheatsheet
Before we get our hands dirty, please print out your very own Linux Command Line Cheatsheet. It's a good reference to have, so print it out and tape it to your wall where it's clearly visible!
VMware - Recommended Setup for All Users
If you're having trouble with any of the setup, try Googling error messages or commenting below!
Alternatives to VMware
Mac OS X Users
If you're on a Mac, you're partly in luck! Mac is built on top of a Unix platform, meaning it comes equipped with its own terminal with commands that are very similar to that of Linux.
To open the terminal, simply search for "Terminal" in your launcher, (⌘+Space).
If you want a highly customizable, and more pleasant version of the Terminal, I recommend you download iTerm2.
The Mac OS X command line is very similar to Linux Command Line, but you'll see a few commands are a tad bit different.
If you're on a Windows, simply download Cygwin, which allows for a similar interface as a terminal on a Unix platform.
If you're on Windows 10, it will be better to simply install the Bash Shell.
If you're running Linux, there is a Terminal you can launch by searching "Terminal." On Ubuntu, you can easily open this by holding Ctrl+Alt+T.
Keyboard inputs and outputs in this tutorial series
$ # All commands in this tutorial are preceded with a $. # All outputs will be printed on the next line. # Any code in italics are just example options, files or directory names.
Let's now get to it!
Introduction to the Shell $PATH, cal, exit
When we talk about the command line we actually are referring to the shell.
The shell takes whatever you type in, searches for that command in the directories list in your
$PATH variable then runs them through the operating system.
Checking the directories in $PATH
To take a look at the
$PATH variable type
$ echo $PATH
Each directory is separated by a colon (:). We'll look more in-depth about the
$PATH variable, and the
echo command soon.
Viewing available binaries
For now, let's look at the contents within one of the folders in our path. We can do this with the
ls command. Let's look in one of our bin folders, which is short for binaries.
$ ls /usr/bin
... corelist cpan cpan2dist cpanp cpanp-run-perl cpp cpp-4.8 crc32 ...
You should get a long list of commands that are available to you. We'll learn more about folders, the file system and the
ls command soon, but just know that the commands you enter in the command line actually come from executable files and not from thin air.
Now try typing some random letters into your terminal.
-bash: asdf: command not found
You should get an error. This is because it's not a command that lives in one of our
A simple command
Now try the calendar command,
cal, which outputs the current month's calendar.
May 2016 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
There are tons more commands you can use, and even more you can install and write yourself!
In this tutorial series, we'll learn the most commonly used commands, and learn some practical concepts of using the Linux Command Line. Through learning about the commands, we'll slowly begin to transition into learning about the Linux Operating System as a whole.
Exiting like a champ
To exit the terminal from the command line, use:
Command Structure commands, options, arguments
Before we take a look into some commands, let's take a formal look at how they are structured.
Three main components of a command
There are three main components that go into a command.
When entering a command, order matters. It's important to place the command name first - otherwise, the shell won't know how to process your submission.
Most commands come with certain options, which modify how the command is run. To apply an option, trail it immediately after your command with a hyphen (-).
There is also a long option form of each short option that uses two hyphens (--). We'll stick to the short option for the sake of brevity.
$ command -shortOptions $ command --longOptions
Note that some commands that we'll discuss in the future have actions instead of options. For example, when we later learn about package management, we'll see that some commands use actions words (eg.
apt-get install packagename.deb instead of options.
An argument is some information you pass to the command when it is started.
$ command -options arguments
You may have multiple options and arguments, as we'll discuss real soon.
How commands are interpreted
We can use the
type command to see how our shell interprets our command.
1) As a shell builtin
One of the many possibile ways that the shell may interpret a command is as a shell builtin. This means that the command is called from the shell and directly executed in the shell itself.
$ type type
type is a shell builtin
2) As an external program
Commands may also be loaded and run from an external file.
$ type ls
ls is hashed (/bin/ls)
3) As an alias
Another way a command can be referenced is through user-defined aliasing. In the example below, we aliased
db to guide us to our Dropbox directory. We'll learn how to implement an alias real soon.
$ type db
db is aliased to `cd ~/Dropbox'
Commenting in the shell
To comment in the shell, use the pound (
#) symbol. Anything after
# will be ignored.
The Linux File System pwd, ls, cd
What is a File System?
Computers organize their files using a tree-like structure known as a file system.
Linux has a single file tree system, which starts with the root directory (/). On a Windows, the "root" would be something like C:\.
The following image shows what a Linux File System would look like.
In Linux, almost everything is represented as a file (or directory) on the File System. This includes USB devices and hard disks, which are stored under /dev.
A filename can contain uppercase or lowercase letters, numbers and most punctuation characters. Note that filenames are case sensitive!
Some files begin with a dot (.) and are used for configuration settings. Others can end with a tilden (~), denoting that it is a backup file. Furthermore, we'll see how we can use ? and * to denote special cases when we learn about wildcards and globbing. Although you can name your files with these symbols, it's highly not recommended.
Checking your Current Directory
You can check to see where you are along this file system with the
pwd command (short for "print working directory").
Here, we can see that we are in our FunStuff directory, which is within our Dropbox folder.
Navigating the File System cd
Now that we are able to see the directories we can navigate to, we can move into them.
To navigate into a directory, use the
cd command, and specify a pathname:
$ cd path/to/directory
Relative and Absolute paths
There are two ways you can specify a path - relative and absolute.
When we talk about relative paths, we are referencing relative to the current working directory (where we are in the file system).
For example, if we were in the Dropbox directory, and wanted to move into FunStuff, the relative path would simply be FunStuff.
Note that we can only call this relative path if we are in a certain directory.
Absolute paths, on the other hand, start at the root of the File System (/) and can called wherever you are in the file system.
For example, /home/Dropbox/FunStuff/ would be an absolute path since it starts at the root directory and we can reference it from anywhere along the file system.
Here are some shortcut notations to directories.
- Root Directory
- Current Directory
- Parent Directory
- Home Directory
- Previous Directory
cd command with one of the above directory shortcuts!
$ cd / # change to root directory $ cd - # change to folder you were previously in $ cd .. # change to the parent directory (one directory up the file system)
Listing files ls, -a, -l
Listing directory files with ls
When you start up a terminal session, you are placed within your home directory (denoted by a
To list contents of your current working directory, simply use the
ls command (short for list).
file1.txt file2.txt file3.txt file4.txt
Here, we can see that four text files reside in our current working directory.
Additionally, you can list files within other directories by specifying the pathname after the
$ ls ~/Dropbox
Books Library Movies School Work
Listing hidden files with the -a option
Hidden files are usually those that have to do with the configuration of certain programs. They are kept hidden from the user, and have a . preceding its name.
For example, the .bash_profile file, located in your home directory, is run every time you start a new terminal to configure your environment. Furthermore the .vimrc file configures your Vim settings.
However, you can't see these files with a normal
To list the hidden files use the option
$ ls -a
. Applications Library .. Desktop Movies .bash_history Documents Music .bash_profile Downloads Public .vimrc Dropbox
Can you see your secret files now?
Listing file details with the -l option
To see more details of the files, we can pass the
You should see a list of files with the following format (don't worry if your date format isn't exactly the same):
$ ls -l
total 12 drwx------ 6 JohnDoe staff 204 Jan 7 10:30 Applications drwx------+ 37 JohnDoe staff 1258 Mar 20 17:58 Desktop drwx------+ 6 JohnDoe staff 204 Mar 13 08:57 Documents drwx------+ 29 JohnDoe staff 986 Mar 22 00:06 Downloads drwx---rwx@ 25 JohnDoe staff 850 Mar 20 15:38 Dropbox drwx------@ 51 JohnDoe staff 1734 Mar 17 17:42 Library drwx------+ 3 JohnDoe staff 102 Dec 29 00:00 Movies drwx------+ 3 JohnDoe staff 102 Dec 29 00:00 Music drwxr-xr-x 4 JohnDoe staff 136 Mar 13 11:15 NetBeansProjects drwx------+ 4 JohnDoe staff 136 Dec 29 20:39 Pictures drwxr-xr-x+ 5 JohnDoe staff 170 Dec 29 00:00 Public drwx------ 4 JohnDoe staff 136 Mar 20 11:31 VirtualBox VMs
Let's break this down per attribute.
- Access file rights. We will talk about this when we go over permissions.
- The file's number of hard links. We will talk about links in our links lesson.
- The file's owner.
- The file's group owner.
- Size of file in bytes (kb).
- Dec 21 16:02
- Date and time of file's last modification.
- Name of file.
Other options to use with ls
There are other options you can use, but
-a are the most common.
- List all entries except for implied . and ..
- Indicator samp to see what type of file it is.
- / for directory, @ for symbolic link, = for socket, | for pipe.
- Colorized output. Can also use --color on some distros.
- Recursively list subdirectories.
- Lists and sorts results by file size.
- Sorts by modification time.
- Sorts in reverse-alphebetical order.
To combine options, simply places the two together:
$ ls -la
Copying, Moving and Renaming Files and Directories cp
To copy a file into another directory, use the
cp command with the file name as the first argument, and the target path name as the second.
$ cp fileName destination
You may rename the file by attaching it to the end of the path.
$ cp fileName destination/newFileName
This takes a file, and sends a copy of it to the specified path, with the new file name.
And to copy into the same directory with a new name:
$ cp fileName newFileName
To copy directories and the contents within, we must apply the
-r option, which is the command to copy recursively.
The following command would copy all contents of dir1 into dir2.
$ cp -r dir1 dir2
Copying multiple files in one go!
We can copy multiple items at once into a directory. As long as the last argument is the path name, we're good.
$ cp file1 file2 file3 pathName
Here are some additional options for fine-tuning.
- Force overwriting.
- Interactive mode. The program will ask before overwriting any files.
- Preserves ownership and permissions.
- Perform archive. Preserves ownership and copies links as is.
- Update. Only copy the file if original is newer than target (or if target does not exist).
Moving and Renaming files mv
Moving and renaming are performed with the same command,
To move a file, use the
Our last argument should be the target path to that directory.
$ mv file1 file2 file3 dir1/
Creating good habits
A good habit to form is to make sure that your target path ends with a / if you are using a directory. Having the / at the end tells the shell that the destination is a directory. Check out how the shell notifies you that the directory does not exist when we accidently commit a typo.
$ mv file1 /home/JohnDoe/diretcry/
mv: rename file1 to /home/JohnDoe/diretcry/: No such file or directory.
If we were to omit the /, the shell would assume that we are trying to move our file to /home/JohnDoe and rename our file to diretcry.
We can use
mv command to move a file to your current directory with a new name (in other words, rename it).
$ mv oldFileName newFileName
mv shares common options with
- Interactive mode. Before overwriting a file, prompt the user.
- Update. Copy only files that either don't exist or are newer than the existing corresponding files in the destination directory.
- Verbose. Ouput messages as they are being copied.
Making Files and Directories touch, mkdir
Creating empty files
To make an empty file, use the
$ touch file1 file2 file3
Managing a file's timestamp
touch command is built for much more than just creating empty files. It can be used to update timestamps. Specify a particular option to modify a certain time attribute.
- Modifiy the access time.
- Change the modification time.
- Do not create any files that already exist.
- -t timestamp
- Set the timestamp in the form MMDDhhmm[[CC]YY][.ss]. MM
- MM is month, DD is day, hh is hour, mm is minute, CC[YY] is year, and ss is second.
- -r reffile
- Replicate the timestamps from another file.
This command can also be used to update the access date or modification date of a file or directory.
You can access the modification time with a simple
ls -l command.
To make a directory, simply use the
$ mkdir dir1 dir2 dir3
This makes a directory named dir1, dir2 and dir3.
Removing files and directories
To remove (aka delete) a file, use the
$ rm file1
To remove an entire directory, add the
-r option, which means to delete recursively. You may also use the
rmdir command, but this only works if the directory is empty.
$ rm -r dir1
Deleting without the
-r option results in an error.
Be careful when deleting!
Be careful when you delete! There is no undelete command, although some distros implement some sort of recyling bin.
Options for removing
Here are some useful options to use for the
- Force. Ignore nonexistent files (for use with wildcards)
- Interactively. Prompts user for permission for each file to be deleted.
- Verbose. Displays informative messages as deletions are being performed.
Great work! Now let's turn to more intermediate commands.