UNIX for Advanced & Expert Users

Hello,

This is a bit of an odd question. Most commends like echo $HOME will just print /home/user_name . I have a system where /home is mounted in a directory that is not under / and is also not its own partition.

There is a partition that is mounted in fstab with,

Code:

# shared linux data partition, /home is here by a bind mount
UUID=a89334f7-59b7-4d04-b89b-a5a30c379644  /mnt/linux_data  ext4  defaults  1 2

The home directory is mounted using a bind mount,

Code:

# bind mount /home to directory to a directory on /linux_data
/mnt/linux_data/01_centos  /home   none  bind   0 0

If I click on the home directory icon in dolphin, the location bar indicates /home/user_name as I would expect. Under the hood, this directory should actually be the directory /mnt/linux_data/01_centos/user_name which does exist in that location. I can navigate to /mnt/linux_data/01_centos/user_name by going through the /root icon in dolphin but I would like some means to print the full path to what the OS believes to be /home .

I am having some issues getting dolphin to display the rest of the partition that /home is mounted on and I would like to start by confirming that /home is where I think that it is. Am I making any sense at all???

LMHmedchem

Do the commands realpath or readlink (with or without -f) help here at all?

Or perhaps the Cwd module from perl:

Code:

perl -MCwd -e 'print Cwd::realpath($ARGV[0])' /home/user_name

I have tried the following where dpi.txt is a file in /home/user_name

Code:

$ pwd
/home/user_name

realpath dpi.txt
realpath -L dpi.txt
realpath -P dpi.txt

All of these result in /home/user_name/dpi.txt

The perl code output looked a bit odd be seemed to print the same thing. The readlink command gave the same results a realpath.

It looks like findmnt may give me what I need. Skipping allot of stuff,

Code:

├─/mnt/linux_data                     /dev/sdb3   ext4      rw,relatime,seclabel,data=ordered
├─/home                               /dev/sdb3[/01_centos]

This seems to indicate that /home is located on /dev/sdb3/01_centos , which is /mnt/linux_data/01_centos which is expected.

LMHmedchem

It does not make sense to me.
The purpose of the bind mount is to let it appear under /home/ - why do you want to break it?

I was just trying to confirm that /home was actually mounted at the partition/directory I specified in fstab. I have more than one copy of /home and I wanted to make sure that the version I was looking at in dolphin through the home icon was at the location I was expecting.

As I understand it, when the OS can't find /home where you have specified, the OS will create a /home under / . If you then specify a new /home in a different location (partition etc), the original /home under / will still exist but not be accessible. I wasn't sure how to tell which /home I was looking at. Later, I was curious as to why I couldn't find a simple way find that information and decided to post a question.

I have another related issue I am trying to resolve. I will make another thread about that this afternoon but I first wanted to confirm that my fstab entries were mounting /home where I wanted it.

LMHmedchem

So basically you want to confirm that /home is on the /mnt/linux_data partition rather than /? You could check out the stat command:

Code:

stat -c%d "${HOME}"

This will give the device number of the partition you are on in decimal. By comparing it with, say, the device number of / you know whether it is on the root or a different partition. Unfortunately stat doesn't give access to the UUID of the device (that I could see, anyway).

While this doesn't in itself confirm that the home directory is mounted on the correct partition, once you have the correct device number you could write a script with that id preloaded into the script.


Of course, all this will have to be done with a script or on the command line, and not, as you initially wished, in the file manager (Dolphin).


Andrew