Linux Filesystem Hierarchy Version 0.65 Binh Nguyen <linuxfilesystem(at)yahoo(dot)com(dot)au> 2004−07−30 This document outlines the set of requirements and guidelines for file and directory placement under the Linux operating system according to those of the FSSTND v2.3 final (January 29, 2004) and also its actual implementation on an arbitrary system. It is meant to be accessible to all members of the Linux community, be distribution independent and is intended to discuss the impact of the FSSTND and how it has managed to increase the efficiency of support interoperability of applications, system administration tools, development tools, and scripts as well as greater uniformity of documentation for these systems. Copyright 2003 Binh Nguyen Trademarks are owned by their owners. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2; with no Invariant Sections, with no Front−Cover Texts, and with no Back−Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". Linux Filesystem Hierarchy Table of Contents Source and pre−formatted versions available..................................................................................................1 Chapter 1. Linux Filesystem Hierarchy............................................................................................................2 1.1. Foreward...........................................................................................................................................2 1.2. The Root Directory...........................................................................................................................6 1.3. /bin....................................................................................................................................................7 1.4. /boot..................................................................................................................................................9 1.5. /dev..................................................................................................................................................10 1.6. /etc...................................................................................................................................................15 1.7. /home..............................................................................................................................................48 1.8. /initrd...............................................................................................................................................49 1.9. /lib...................................................................................................................................................50 1.10. /lost+found....................................................................................................................................51 1.11. /media............................................................................................................................................52 1.12. /mnt...............................................................................................................................................53 1.12.1. Mounting and unmounting..................................................................................................53 1.13. /opt................................................................................................................................................56 1.14. /proc..............................................................................................................................................56 1.15. /root...............................................................................................................................................78 1.16. /sbin...............................................................................................................................................79 1.17. /usr................................................................................................................................................80 1.18. /var................................................................................................................................................84 1.19. /srv................................................................................................................................................87 1.20. /tmp...............................................................................................................................................88 Glossary.............................................................................................................................................................89 Appendix A. UNIX System V Signals.............................................................................................................95 Appendix B. Sources.........................................................................................................................................96 Appendix C. About the Author........................................................................................................................99 Appendix D. Contributors..............................................................................................................................100 Appendix E. Disclaimer..................................................................................................................................101 Appendix F. Donations...................................................................................................................................102 Appendix G. Feedback...................................................................................................................................103 Appendix H. GNU Free Documentation License.........................................................................................104 H.1. PREAMBLE................................................................................................................................104 H.2. APPLICABILITY AND DEFINITIONS....................................................................................104 H.3. VERBATIM COPYING..............................................................................................................105 H.4. COPYING IN QUANTITY.........................................................................................................106 H.5. MODIFICATIONS......................................................................................................................106 H.6. COMBINING DOCUMENTS.....................................................................................................107 i Linux Filesystem Hierarchy Table of Contents Appendix H. GNU Free Documentation License H.7. COLLECTIONS OF DOCUMENTS..........................................................................................108 H.8. AGGREGATION WITH INDEPENDENT WORKS.................................................................108 H.9. TRANSLATION..........................................................................................................................108 H.10. TERMINATION........................................................................................................................109 H.11. FUTURE REVISIONS OF THIS LICENSE.............................................................................109 H.12. ADDENDUM: How to use this License for your documents...................................................109 Notes..............................................................................................................................................110 ii Source and pre−formatted versions available The source code and other machine readable formats of this book can be found on the Internet at the Linux Documentation Project home page http://www.tldp.org The latest version of this document can be found at http://cvsview.tldp.org/index.cgi/LDP/guide/docbook/Linux−Filesystem−Hierarchy/ Source and pre−formatted versions available 1 Chapter 1. Linux Filesystem Hierarchy 1.1. Foreward When migrating from another operating system such as Microsoft Windows to another; one thing that will profoundly affect the end user greatly will be the differences between the filesystems. What are filesystems? A filesystem is the methods and data structures that an operating system uses to keep track of files on a disk or partition; that is, the way the files are organized on the disk. The word is also used to refer to a partition or disk that is used to store the files or the type of the filesystem. Thus, one might say I have two filesystems meaning one has two partitions on which one stores files, or that one is using the extended filesystem, meaning the type of the filesystem. The difference between a disk or partition and the filesystem it contains is important. A few programs (including, reasonably enough, programs that create filesystems) operate directly on the raw sectors of a disk or partition; if there is an existing file system there it will be destroyed or seriously corrupted. Most programs operate on a filesystem, and therefore won't work on a partition that doesn't contain one (or that contains one of the wrong type). Before a partition or disk can be used as a filesystem, it needs to be initialized, and the bookkeeping data structures need to be written to the disk.