JP Vossen on 15 Jul 2010 12:15:23 -0700

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Re: [PLUG] Laptop recovery--useful data to collect?--A tangent

Date: Thu, 15 Jul 2010 05:31:24 -0400
From: LeRoy<>

... /var/tmp is a symlink to /tmp ...

That is severely broken and a Bad Idea because it is a violation of the Filesystem Hierarchy Standard (FHS).

--- quote ---

/tmp : Temporary files

The /tmp directory must be made available for programs that require temporary files.

Programs must not assume that any files or directories in /tmp are preserved between invocations of the program.


IEEE standard P1003.2 (POSIX, part 2) makes requirements that are similar to the above section.

Although data stored in /tmp may be deleted in a site-specific manner, it is recommended that files and directories located in /tmp be deleted whenever the system is booted.

FHS added this recommendation on the basis of historical precedent and common practice, but did not make it a requirement because system administration is not within the scope of this standard.

/var/tmp : Temporary files preserved between system reboots

The /var/tmp directory is made available for programs that require temporary files or directories that are preserved between system reboots. Therefore, data stored in /var/tmp is more persistent than data in /tmp.

Files and directories located in /var/tmp must not be deleted when the system is booted. Although data stored in /var/tmp is typically deleted in a site-specific manner, it is recommended that deletions occur at a less frequent interval than /tmp.

--- end quote ---

Despite sometimes seeming very odd or arbitrary, the Unix/Linux file system is set up in specific ways for a reason. Don't mess with it (I'm looking at you Apple!).

(OK, yes, some of those reasons are no longer as important as they once were, what with larger disks and untrusted networks. Still... Go read the FHS, it's an interesting look at *why* things are the way they are. Also, go read _Absolute FreeBSD_; you will learn a lot more about *why* things are the way they are and *why* things work the way they work.)

JP Vossen, CISSP            |:::======|
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