Linux home directory files

Linux Directory Structure Explained for Beginners

This tutorial explains the Linux directory structure. You’ll learn the Linux filesystem hierarchy along with the purpose of the various directories on a Linux system.

If you are even faintly acquainted with Linux, you might have heard the terms root, lib, bin etc. These are various directories that you’ll find in all Linux distributions.

In fact, the Linux Foundation maintains a Filesystem Hierarchy Standard (FHS). This FHS defines the directory structure and the content/purpose of the directories in Linux distributions. Thanks to this FHS, you’ll find the same directory structure in (almost) all the Linux distributions.

Let’s see the Linux directory structure in detail.

Linux directory structure

Linux is based on UNIX and hence it borrows its filesystem hierarchy from UNIX. You’ll fine a similar directory structure in UNIX-like operating systems such as BSD and macOS. I’ll be using the term Linux hereafter instead of UNIX though.

/ – The root directory

Everything, all the files and directories, in Linux are located under ‘root’ represented by ‘/’. If you look at the directory structure, you’ll realize that it is similar to a plant’s root.

Since all other directories or files are descended from root, the absolute path of any file is traversed through root. For example, if you have a file in /home/user/documents, you can guess that the directory structure goes from root->home->user->documents.

The cruel rm -rf / joke

You may have come across some jokes on internet that mentions “rm -rf /” . rm command is used for removing files and directories in Linux.

With rm -rf /, you ask your system to forcefully and recursively delete the contents of the root directory. Since root directory has everything underneath, you end up deleting everything and your Linux system just vanishes (theoretically).

Most Linux distribution won’t run this command unless you provide –no-preserve-root. In any case, don’t be curious to run this command. Curiosity killed the cat, after all.

/bin – Binaries

The ‘/bin’ directly contains the executable files of many basic shell commands like ls, cp, cd etc. Mostly the programs are in binary format here and accessible by all the users in the Linux system.

/dev – Device files

This directory only contains special files, including those relating to the devices. These are virtual files, not physically on the disk.

Some interesting examples of these files are:

• /dev/null: can be sent to destroy any file or string
• /dev/zero: contains an infinite sequence of 0
• /dev/random: contains an infinite sequence of random values

/etc – Configuration files

The /etc directory contains the core configuration files of the system, use primarily by the administrator and services, such as the password file and networking files.

If you need to make changes in system configuration (for example, changing the hostname), this is where you’ll find the respective files.

/usr – User binaries and program data

in ‘/usr’ go all the executable files, libraries, source of most of the system programs. For this reason, most of the files contained therein is read­only (for the normal user)

• ‘/usr/bin’ contains basic user commands
• ‘/usr/sbin’ contains additional commands for the administrator
• ‘/usr/lib’ contains the system libraries
• ‘/usr/share’ contains documentation or common to all libraries, for example ‘/usr/share/man’ contains the text of the manpage

/home – User personal data

Home directory contains personal directories for the users. The home directory contains the user data and user-specific configuration files. As a user, you’ll put your personal files, notes, programs etc in your home directory.

When you create a user on your Linux system, it’s a general practice to create a home directory for the user. Suppose your Linux system has two users, Alice and Bob. They’ll have a home directory of their own at locations /home/alice and /home/bob.

Do note that Bob won’t have access to /home/alice and vice versa. That makes sense because only the user should have access to his/her home. You may read about file permissions in Linux to know more on this topic.

/lib – Shared libraries

Libraries are basically codes that can be used by the executable binaries. The /lib directory holds the libraries needed by the binaries in /bin and /sbin directories.

Libraries needed by the binaries in the /usr/bin and /usr/sbin are located in the directory /usr/lib.

/sbin – System binaries

This is similar to the /bin directory. The only difference is that is contains the binaries that can only be run by root or a sudo user. You can think of the ‘s’ in ‘sbin’ as super or sudo.

/tmp – Temporary files

As the name suggests, this directory holds temporary files. Many applications use this directory to store temporary files. Even you can use directory to store temporary files.

But do note that the contains of the /tmp directories are deleted when your system restarts. Some Linux system also delete files old files automatically so don’ store anything important here.

/var – Variable data files

Var, short for variable, is where programs store runtime information like system logging, user tracking, caches, and other files that system programs create and manage.

The files stored here are NOT cleaned automatically and hence it provides a good place for system administrators to look for information about their system behavior. For example, if you want to check the login history in your Linux system, just check the content of the file in /var/log/wtmp.

/boot – Boot files

The ‘/boot’ directory contains the files of the kernel and boot image, in addition to LILO and Grub. It is often advisable that the directory resides in a partition at the beginning of the disc.

/proc – Process and kernel files

The ‘/proc’ directory contains the information about currently running processes and kernel parameters. The content of the proc directory is used by a number of tools to get runtime system information.

For example, if you want to check processor information in Linux, you can simply refer to the file /proc/cpuinfo. You want to check memory usage of your Linux system, just look at the content of /proc/meminfo file.

/opt – Optional software

Traditionally, the /opt directory is used for installing/storing the files of third-party applications that are not available from the distribution’s repository.

The normal practice is to keep the software code in opt and then link the binary file in the /bin directory so that all the users can run it.

/root – The home directory of the root

There is /root directory as well and it works as the home directory of the root user. So instead of /home/root, the home of root is located at /root. Do not confuse it with the root directory (/).

/media – Mount point for removable media

When you connect a removable media such as USB disk, SD card or DVD, a directory is automatically created under the /media directory for them. You can access the content of the removable media from this directory.

/mnt – Mount directory

This is similar to the /media directory but instead of automatically mounting the removable media, mnt is used by system administrators to manually mount a filesystem.

/srv – Service data

The /srv directory contains data for services provided by the system. For example, if you run a HTTP server, it’s a good practice to store the website data in the /srv directory.

I think this much information is enough for you to understand the Linux directory structure and its usage.

In the end, if you want, you can download and save this image for quick reference to the directory structure in Linux systems.

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Linux directory structure: /home and /root folders

This is our 6th post on understanding first level directories in /. Knowing these folders in detail or at least what each is meant for will help you understand Linux/Unix in whole. we already covered below directories, please have a look at those to understand them. In this post we will see two more directories ie /home and /root directory. These directories are meant for similar purpose. The /root is meant for just root user and /home is for all the remaining users.

A brief intro to /home directory in Linux/Unix

The /home directory is a place where by default all user home directories are created.

OK, what are user home directories for?

These directories are a kind of personal place(Working space) for all the users other than root. There will be a separate folder for each user in /home directory. For example if you have a user called ‘Tom’, then his default home directory is /home/tom. We can change this default folder when creating user in Linux. Our Tom user can do what ever he wants in /home/tom folder where he have full rights on the files he created and owned in that folder.

The properties of /home folder?

1) A separate sub folder ie /home/ is present for each user.
2) Only user who owns this sub folder can access it’s content other than root user. So, tom user can not access Barbi user home directory content which is located at /home/barbi.
3) All his terminal properties, command history file, application setting files(~/.vimrc, ~/.ssh) etc everything is located in this folder.
4) System admins when try to implement quota for users they will implement it on /home directory. This /home directory should be mounted on a separate partition.

Each user home directory is important and frequently used directory for that user, we have alias name for it. This alias is set to ~ so that when ever user wants to navigate to his home directory, he do not have to use /home/ but just use below short cuts.

Will take you to your home directory.

When you are in your home directory even our PS1 prompt will show user’s home directory with ~.

xyz@sanne-taggle:/home$ cd xyz@sanne-taggle:~$ pwd /home/xyz

Some of the important files which are present in /home/ or /root directory are as below.

1) Bash shell related configuration files.
.bashrc
.bash_history
.bash_profile
.bash_logout

If your shell is not bash then you should see other shell configuration files.

2) Default editor configuration files.
3) You secure shell configuration files are located in ~/.ssh which contain your ssh-keys, knownhosts etc.

How about /root directory in Linux?

This is root’s home directory. Do not get confused between / and /root. Both these are meant for different purpose.

/ is the main folder where your file system resides, where as /root is root user home directory. Similar to /home/, root user saves his personal data, terminal configurations in /root directory.

Some FAQ on user home directories

Why is home directory of root is a separate folder?

Because of security reasons root’s home directory is separated from /home.

I see many users in /etc/passwd but I don’t see them in /home, why?

This can be of two reasons.
1) Either users are system defined users
2) Or users home directory resides some where else.
3) Or intentionally /home directory is not created. For this type of users / will be treated as their home directory. This is a nightmare as he can not do anything in / folder due to lack of permissions.

In our next post we will see lib folder.

Surendra Anne

Mr Surendra Anne is from Vijayawada, Andhra Pradesh, India. He is a Linux/Open source supporter who believes in Hard work, A down to earth person, Likes to share knowledge with others, Loves dogs, Likes photography. He works as Devops Engineer with Taggle systems, an IOT automatic water metering company, Sydney . You can contact him at surendra (@) linuxnix dot com.

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