Unix File Structure

Single rooted tree at /. Instead of separate trees (as with disk partitioning), volumes can be mounted on a directory. Two-disk setups used to be common, with first disk with startup programs and second mounted as /usr.

/bin

Contains binaries, including fundamental utilities like ls and cp used to mount /usr. This is loaded in the $PATH which exposes these binaries as commands from your shell.

/boot

Contains files required for booting process

/etc

System-wide configuration files and system databases.

/dev

Location of special or device files. Files here can represent external devices like speakers, or data volumes.

• contains partitions of hard drives (hd1, hd2). Representing devices as files means that we can write data to a file and it is consumed by the device, the speaker file will play sound if you write text into it.
• fdisk -l shows disk devices and their partitions
  • for manipulating disk partition tables
  • sda for example might be partitioned into sda1, sda2, etc
• df shows disk space by volume on the system
• lsblk (list block) shows name, type and mountpoint for all available block devices which is probably the same as the output of fdisk -l; it excludes RAM disks

/home

Contains user home directories. OSX useds /Users instead.

lib

Contains shared libraries needed by programs in /bin

/media

Default mount point for removable devices

/opt

Locally installed software.

/proc

procfs virtual filesystem showing informaiton about processes as files

/root

Home directory for superuser "root".

/sbin

System binaries, containing fundamental utilities like init for start, maintain, and recovery of system.

/usr

User file system. Holds executables , libraries, shared resources not system critical.

• /include stores development header files.
• /lib stores required libraries and data files for programs stored in /usr
• local custom programs or files

/var

Variable, place for files that change often.

• /log contains system log files
• /tmp directory for temporary files which should be preserved between system reboots