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How to check whether or not a particular directory is a mount point? For instance there is a folder named /test that exists, and I want to check if it is a mount point or not.

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    You don't mount directories on Linux. You mount devices to particular directories. Checking to see if something is mounted is as simple as looking at the output of the mount command. Commented Aug 21, 2014 at 14:01
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    Let's help, perhaps they do not understand this finer point! Commented Aug 21, 2014 at 14:02
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    The answers below will show you how to examine the mount table, but a simpler solution is to create a file in the mount point directory before anything is mounted on it. Call it anything you like, but one example is NOTMOUNTED. When you can see the file, the directory is not a mount point, and when you don't, it is. Commented Aug 21, 2014 at 14:13
  • What would be a C level solution ? Commented Aug 27, 2024 at 17:04
  • I found this very useful, and not a duplicate as stated. Suggest the wording "How can I check whether a filesystem is currently mounted on a particular directory?". The correct answer is unix.stackexchange.com/a/151401/582221 Commented Aug 23 at 9:50

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If you want to check it's the mount point of a file system, that's what the mountpoint command (on most Linux-based systems) is for:

if mountpoint -q -- "$dir"; then printf '%s\n' "$dir is a mount point" fi

It does that by checking whether . and .. have the same device number (st_dev in stat() result). So if you don't have the mountpoint command, you could do:

perl -le '$dir = shift; exit(1) unless (@a = stat "$dir/." and @b = stat "$dir/.." and ($a[0] != $b[0] || $a[1] == $b[1]))' "$dir"

Like mountpoint, it will return true for / even if / is not a mount point (like when in a chroot jail), or false for a mount point of a bind mount of the same file system within itself.

Contrary to mountpoint, for symbolic links, it will check whether the target of the symlink is a mountpoint.

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    At least on Ubuntu, the output of mountpoint already says "$dir is a mountpoint" ,so you don't need the if part around it. Commented Sep 17, 2016 at 9:49
  • @SergiyKolodyazhnyy the -q means quiet output, so in this case, the output is being suppressed and then replaced by custom output. Unnecessary, but yeah. Commented Jul 25, 2017 at 19:49
  • @Wyrmwood I know what the options are. What I'm saying is that mountpoint "$dir" already does exactly the same as the 3-line if statement does here. Functionally they're the same. Such use of mountpoint -q in if statement can be used when you want to perform some action based on the exit status, but for printing the message to user its unnecessary - it's already the default behavior of the program. Commented Jul 25, 2017 at 20:21
  • How can I install mountpoint into macOS? I have tried through brew but system is unable to see it Commented Apr 14, 2022 at 12:35
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As HalosGhost mentions in the comments, directories aren't necessarily mounted per se. Rather they're present on a device which has been mounted. To check for this you can use the df command like so:

$ df -h /boot/ Filesystem Size Used Avail Use% Mounted on /dev/hda1 99M 55M 40M 59% /boot

Here we can see that the directory /boot is part of the filesystem, /dev/hda1. This is a physical device, on the system, a HDD.

You can also come at this a little bit differently by using the mount command to query the system to see what devices are currently mounted:

$ mount | column -t /dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/hda1 on /boot type ext3 (rw) tmpfs on /dev/shm type tmpfs (rw) /dev/mapper/lvm--raid-lvm0 on /export/raid1 type ext3 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) nfsd on /proc/fs/nfsd type nfsd (rw)

Here you can see the type of device and the type of filesystems are currently mounted on your system. The 3rd column shows where they're mounted on the system within its filesystem.

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    To check if a particular directory is an active mountpoint (especially in scripts, where a binary result is handy), the mountpoint command is a nice alternative e.g. if mountpoint -q /path/to/dir; then .... I'm not sure how widely available it is though. Commented Aug 21, 2014 at 14:14
  • @steeldriver - cool, never seen that one before. It's present on my Red Hat distros. Commented Aug 21, 2014 at 14:20
  • @slm: Am I going blind, or was your cat walking on your keyboard when you posted this answer?  It says, “Here we can see that the directory /usr is part of the filesystem, …”, but /usr appears nowhere else in the answer. Commented Dec 6, 2015 at 23:54
  • @G-Man - I meant to type /boot there, I fixed it. Given the above example shows /boot it seemed pretty obvious what I meant when I typed that, even with the typo. Commented Dec 7, 2015 at 3:17
  • Why not just mounpoint $(pwd) ? It prints /jail/bin is a mountpoint. Btw, I think findmnt of @xharx 's answer is the best. Commented May 25, 2022 at 7:16
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I was looking for the same question when I wanted to check mounting a new XFS filesystem.

I found the command findmnt: findmnt /directoryname

[root@CentOS7-Server /]# findmnt /mnt TARGET SOURCE FSTYPE OPTIONS /mnt /dev/sdb1 xfs rw,relatime,seclabel,attr2,inode64,noquota [root@CentOS7-Server /]#
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  • very concise solution! Commented May 11, 2021 at 22:07
  • This is the best. findmnt gives the most informative output compared to some others. That is, it tells which specific diretory is the target mounted from. One can run findmnt with no arguments. Commented May 25, 2022 at 7:15
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Well, as others said you should edit your question and make it clear on what you are trying to achieve. As far as I understood, you need to check if a directory is mounted to a particular device. You can try something like below as well. 

df -P /test | tail -1 | cut -d' ' -f 1

So basically, the above command lets you know the mount point of the directory if at all the device is mounted to a directory.

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  • This one is what I was looking for. Thanks for sharing. Commented Sep 7, 2022 at 19:03
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Nice and short Python one-liner can be constructed based on Gilles' answer:

$ python -c 'import os,sys;print(os.path.ismount(sys.argv[1]))' /mnt/HDD True $ python -c 'import os,sys;print(os.path.ismount(sys.argv[1]))' /etc False

I've made custom implementation of mountpoint command in Python, which parses /proc/self/mounts file. Kind of the same behavior as mount in Stephane's answer, except that command parses /proc/self/mountinfo. Usage is very simple: is_mountpoint.py /path/to/dir.

#!/usr/bin/env python3 from os import path import sys def main(): if not sys.argv[1]: print('Missing a path') sys.exit(1) full_path = path.realpath(sys.argv[1]) with open('/proc/self/mounts') as mounts: print for line in mounts: if full_path in line: print(full_path,' is mountpoint') sys.exit(0) print(full_path,' is not a mountpoint') sys.exit(1) if __name__ == '__main__': main()

Test run:

$ python3 ./is_mountpoint.py /mnt/HDD /mnt/HDD is mountpoint $ lsblk | grep HDD └─sdb6 8:22 0 405.3G 0 part /mnt/HDD $ python3 ./is_mountpoint.py $HOME /home/xieerqi is not a mountpoint
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Your question is little bit confusing, but I guess, one of the ways to check that: mount |awk '{print $3}'| grep -w <your_directory>. If output is empty then no device mounted to the directory . If not empty then some device mounted to the directory. Other way is to use df <your_directory>. If last field equals to your directory name - than some device is mounted to it.

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