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I have a command which is hard-coded to use /tmp as its working directory.

/tmp is rather small, and the command is certain to fill it up, which will cause problems for other system processes.

I can't modify the command, so I would like to remount /tmp somewhere else, only visible to the current user/shell, without affecting other users/processes.

Is this possible?

Update: Discovered the command uses the TMPDIR variable which I can override, but still interested to know if there's a Linux user-space command I can use.

nobody
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bryan_basho
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  • Would a `chroot` help? – Sven Dec 11 '14 at 10:09
  • you can mount /tmp in two places if your /tmp fs isn't incorporate in your root(/) fs, but you cannot umount /tmp with running processes and mounting in other place – c4f4t0r Dec 11 '14 at 10:20

1 Answers1

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The unshare command can do pretty much what you are asking for:

unshare -m "$SHELL"

After that you can change any mounts you like locally to that shell only.

I recommend that any mount commands you run inside the unshared shell use the -n flag, because otherwise it will change /etc/mtab which will be visible to the entire system. You probably want df and mount commands run outside that shell to still show the correct file system mounted on /tmp.

kasperd
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