Meaning of directories on Unix and Unix like systems

For more data on the layout of Linux file-systems, look at the Filesystem Hierarchy Standard (now at version 2.3, with the beta 3.0 version deployed on most recent distros). It does explain some of where the names came from:

  • /bin – Binaries.
  • /boot – Files required for booting.
  • /dev – Device files.
  • /etc – Et cetera. The name is inherited from the earliest Unixes, which is when it became the spot to put config-files.
  • /home – Where home directories are kept.
  • /lib – Where code libraries are kept.
  • /media – A more modern directory, but where removable media gets mounted.
  • /mnt – Where temporary file-systems are mounted.
  • /opt – Where optional add-on software is installed. This is discrete from /usr/local/ for reasons I’ll get to later.
  • /run – Where runtime variable data is kept.
  • /sbin – Where super-binaries are stored. These usually only work with root.
  • /srv – Stands for “serve”. This directory is intended for static files that are served out. /srv/http would be for static websites, /srv/ftp for an FTP server.
  • /tmp – Where temporary files may be stored.
  • /usr – Another directory inherited from the Unixes of old, it stands for “UNIX System Resources”. It does not stand for “user” (see the Debian Wiki). This directory should be sharable between hosts, and can be NFS mounted to multiple hosts safely. It can be mounted read-only safely.
  • /var – Another directory inherited from the Unixes of old, it stands for “variable”. This is where system data that varies may be stored. Such things as spool and cache directories may be located here. If a program needs to write to the local file-system and isn’t serving that data to someone directly, it’ll go here.

/opt vs /usr/local

The rule of thumb I’ve seen is best described as:

Use /usr/local for things that would normally go into /usr, or are overriding things that are already in /usr. Use /opt for things that install all in one directory, or are otherwise special.

Related Posts:

  1. Can’t remove a directory in Unix
  2. cd into directory without having permission
  3. How do I grep recursively?
  4. How do I grep recursively?
  5. How do I find all files containing specific text on Linux?
  6. How do I grep recursively?
  7. How do I use grep to search the current directory for all files having the a string “hello” yet display only .h and .cc files?
  8. SSH using python script
  9. How can I exclude directories from grep -R?
  10. How can I exclude directories from grep -R?
  11. Argument list too long error for rm, cp, mv commands
  12. How to change permissions for a folder and its subfolders/files in one step
  13. Difference between using “chmod a+x” and “chmod 755”
  14. Creating a new directory in C
  15. How to cat <> a file containing code?
  16. Extract file basename without path and extension in bash
  17. Given two directory trees, how can I find out which files differ by content?
  18. How to change permissions for a folder and its subfolders/files in one step
  19. Diff command along with Grep gives “Binary file (standard input) matches”
  20. How to download a file from server using SSH?
  21. What is the difference between “#!/usr/bin/env bash” and “#!/usr/bin/bash”?
  22. What does `set -x` do?
  23. Command to change the default home directory of a user
  24. Using ls to list directories and their total sizes
  25. What does “&” at the end of a linux command mean?
  26. Syntax error near unexpected token ‘then’
  27. C fopen vs open
  28. Restarting cron after changing crontab file?
  29. How do I write stderr to a file while using “tee” with a pipe?
  30. Copying a large directory tree locally? cp or rsync?
  31. Can I nohup/screen an already-started process?
  32. Environment variables of a running process on Unix?
  33. In my /etc/hosts/ file on Linux/OSX, how do I do a wildcard subdomain?
  34. When does /tmp get cleared?
  35. SSL Certificate Location on UNIX/Linux
  36. Is it possible to detach a process from its terminal? (Or, “I should have used screen!”) [duplicate]
  37. What does ‘set -e’ do, and why might it be considered dangerous?
  38. How to remove empty/blank lines from a file in Unix (including spaces)?
  39. How to forcibly close a socket in TIME_WAIT?
  40. How to copy file preserving directory path in Linux?
  41. How can I rename a Unix user?
  42. How to get pid of just started process
  43. Can you have more than one ~/.ssh/config file?
  44. How to disable everything in crontab -l?
  45. How to sort ps output by process start time?
  46. Confused about stdin, stdout and stderr?
  47. What’s a .sh file?
  48. How to fix ‘sudo: no tty present and no askpass program specified’ error?
  49. What does pss mean in /proc/pid/smaps
  50. apt-get error: Sub-process /usr/bin/dpkg returned an error code (1)
  51. How to extract C source code from .so file?
  52. How to substitute shell variables in complex text files
  53. “sed” command in bash
  54. How to exclude a directory in find . command
  55. How can I find all *.js file in directory recursively in Linux?
  56. ssh: Could not resolve hostname [hostname]: nodename nor servname provided, or not known
  57. Python subprocess.Popen “OSError: [Errno 12] Cannot allocate memory”
  58. How to open some ports on Ubuntu?
  59. What does it mean to mount a file system in linux?
  60. What can cause a “Resource temporarily unavailable” on sock send() command
  61. -bash: fork: Cannot allocate memory
  62. Explanation of polkitd Unregistered Authentication Agent
  63. Bash script: bad interpreter
  64. Why should we check WIFEXITED after wait in order to kill child processes in Linux system call?
  65. PHP and mod_fcgid: ap_pass_brigade failed in handle_request_ipc function
  66. How to grep and replace
  67. How to recursively download a folder via FTP on Linux
  68. httpd: Could not reliably determine the server’s fully qualified domain name, using 127.0.0.1 for ServerName
  69. How to include file in a bash shell script
  70. Does Mac OS X use Linux?
  71. bash sh – command not found 
  72. Hosting multiple WordPress sites on single server – best practices?
  73. Check if port is open or closed on a Linux server?
  74. When does `cron.daily` run?
  75. How to run a command multiple times, using bash shell?
  76. How to reconnect to a disconnected ssh session
  77. Should I quit using Ifconfig?
  78. What is “-bash: !”: event not found”
  79. What version of RHEL am I using?
  80. Keeping a linux process running after I logout
  81. Force dig to resolve without using cache
  82. How do you make it obvious you are on a production system?
  83. How to add a timestamp to bash script log?
  84. How can I verify if TLS 1.2 is supported on a remote web server from the RHEL/CentOS shell?
  85. Mount CIFS Host is down
  86. List of files installed from apt package
  87. How to copy a large number of files quickly between two servers
  88. Allow SFTP but disallow SSH?
  89. How can I export the privileges from MySQL and then import to a new server?
  90. Is there a directory equivalent of /dev/null in Linux?
  91. Can I send some text to the STDIN of an active process running in a screen session?
  92. How can I get processor/RAM/disk specs from the Linux command Line? [duplicate]
  93. Is there a way to see the execution tree of systemd?
  94. How to determine the hostname from an IP address in a Windows network?
  95. create home directories after create users
  96. How do I redirect subdomains to a different port on the same server?
  97. Running Cron every 2 hours [duplicate]
  98. How to check the physical status of an ethernet port in Linux?
  99. What does “debconf: delaying package configuration, since apt-utils is not installed” mean?
  100. In Linux, what is the difference between “buffers” and “cache” reported by the free command?

Leave a Comment

tech