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I've been using Linux for a couple of years now but I still haven't figured out what the origin or meaning of some the directory names are on Unix and Unix like systems. E.g. what does etc stand for or var? Where does the opt name come from?

And while we're on the topic anyway. Can someone give a clear explanation of what directory is best used for what. I sometimes get confused where certain software is installed or what the most appropriate directory is to install software into.

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6 Answers 6

up vote 19 down vote accepted

For more data on the layout of Linux file-systems, look at the Filesystem Hierarchy Standard (now at version 2.3).

It explains the purpose of each directory, and even tells you what directory is best to install software into. For most distros, software that doesn't come with the distro probably should go into /usr/local/.

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The document answers the first half of my question very well. However, where the names are derived from is still a mystery. The reason I'd like to know is because I think it will give me more context. –  Luke Jun 12 '09 at 9:31
The naming is nearly all self explanatory. Especially if you read through the descriptions in that link. –  Dan Carley Jun 12 '09 at 9:35
No it isn't. It explains what 'etc' is used for but is doesn't explain where the name comes from or what it stands for. –  Luke Jun 12 '09 at 21:18

Historically, /etc stands for "etcetera" and /var is short for "variable." I suppose the former is because a large collection of unrelated system configuration files go into /etc. The latter is because the files in /var are expected to change. You can often mount /usr and / as read-only (except when performing updates), but you can never mount /var read-only. It hold system logfiles, lock files, spool files, and other things that change dynamically.

Other people gave you pointers to help you figure out what best goes where.

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/opt stands for optional (as in optional add-on packages).

/bin stands for binary (contains executables used by the OS).

/lib stands for library (contains shared libraries used by filesystem and for booting, probably used by the executables in bin)

/proc stands for processes.

/root means root user.

/home holds the home sub-directories for any non-root users.

/dev stands for device (holds special and device files).

/tmp stands for temporary.

/srv stands for serve.

/mnt stands for mount point (mount a temporary filesystem here).

/include contains #include files, i.e. header files (e.g., stdio.h).

/var stands for variable

/etc stands for etcetera

Sorry to resurrect a dead thread, but I feel this detail is an important clarification for all future seekers of this info.

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Nice answer: succinct, directed at the level of the question, and no need to look up other links. +1 –  Scott Biggs Jul 28 at 13:37

The best place to look for this is the Filesystem Hierarchy Standard (FHS). The latest version is 2.3 available at: http://www.pathname.com/fhs/pub/fhs-2.3.html.

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Try this:

$ man hier
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Nice one. However, just like the document referred to in other answers, this man page only talks about what the directories are used for. I'm also interested in why certain names where chosen, like /etc e.g. –  Luke Jun 23 '09 at 22:33
The answer to your question about /etc is here: en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard –  Anonymous Jun 24 '09 at 12:37

Lol well I realize this topic probably died, but yes I think the meaning is important and /etc = etcetera doesn't satisfy my understanding of this folder... so to me E.T.C stands for "Environment Target Configuration" which is much more appropriate... don't you think ;)

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Do you have any 'official' references to this or is just what you think it stands for? I'm interested in the original origin of the names. –  Luke Dec 21 '09 at 6:29

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