The Linux Filesystem

 

/ - The Root Directory

System root

/bin - User Binaries

In single user mode this is where user apps such as firefox etc are stored

/sbin is similar in that is is where administration binaries are stored.

/boot - Static Boot Files

GRUB, linux kernels are stored here, needed to be able to boot the system. Config for boot is stored in /etc

/dev - Device Files

Devices are exposed as files. Eg /dev/sda represents the first SATA drive.

It also contains psuedo-devices. For example: /dev/random produces random numbers.

/dev/null returns no output and discards all input.

/etc - Configuration Files

Contains systems wide configuration files. User specific config files live in each users /home/{user} folder

/home - Home Folders

User specific files and user specific configuration.

/lib - Shared Libraries

Contains essential libraries consumed by binaries in /bin and /sbin.

/usr/lib contains libraries consumed by binaries in /usr/bin

/lost+found Recovered Files

On system crash, recovered files are saved here.

/media - Removable Media

Inside media there are subdirectories that represent removable media such as CDs.

/mnt - Temporary Mount Points

This is where typically temporary file systems are mounted. For example a windows partition. However its possible to mount file systems anywhere on the system.

/opt - Optional Packages

Optional software packages. Typically used by proprietary software that doesn't obey the standard file system hierarchy.

/proc - Kernel and Process Files

Files that contain system and process information and state

/root - Root Home Directory

Root user home directory

/run - Application State Files

Gives apps a place to store transient files such as sockets and process IDs. /tmp cant be used as file in there may be deleted. /run is fairly new.

/sbin - System Administration Binaries

Contains essential binaries needed by the root user for system administration.

/selinux - SELinux Virtual File System

If your linux system uses SELinux for security (Fedora and Red Hat for example), this directory contain special files related to that. Similar to /proc

/srv - Service Data

Contains data for system services. For example if using Apache website files normally reside in /srv

/tmp - Temporary Files

These files are typically deleted upon restart and might be removed intermittently by utilities such as tmpwatch

/usr - User Binaries and Read-Only Data

Read-only user applications (binaries) and read only files use by users.

/usr/bin is used to store user binaries.

/usr/lib is used to store user libraries

/usr/local is where locally compiled applications are installed to, which prevents them from disrupiting the rest of the system.

/var - Variable Data Files

/var is the writable counterpart to the /usr directory which is read only.

Cache, mail, Log files and anything that would need to be written at runtime, are written to the /var directory.

/var/tmp contains user tmp data that needs to be preserved between reboots.

/var/spool/cron contains the variable data for cron jobs.


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