Accessing MTP Mounted Device Via Command Line

When you connect your android phone to a linux box using usb cable, the storage of the phone will appear in your file manager (thanks to automount). It is easily accesible from there, but what if you want to access it via command line? Where is it located?

To know the location of the MTP mounted storage, you need to know your user id

$ id

uid=1000(user) gid=1000(user) groups=1000(user),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),114(lpadmin),134(sambashare)

From the above command, the user ID is 1000. The MTP mounted device can be accessed at /run/user/<user ID>/gvfs

$ ls /run/user/1000/gvfs/

'mtp:host=Android_Android_28f5d3440504'

Just go to the 'mtp:host=Android_Android_28f5d3440504' directory (the name might differ), and you will see your phone's storage.

 

 

 

 

Rename and Remount LVM Logical Volume

A usual scenario where rename and remount of LVM logical volume are needed, is when you install a box with a CentOS, and use the default LVM based partitioning scheme. This scheme will take 50G for your / partition, and the rest will be allocated to your /home, which is not practical. In this example, we will be remounting logical volume originally mounted to /home, to /var/lib/elasticsearch, renaming it along the way.

The original partition scheme 

# df -Th

Filesystem                   Type      Size  Used Avail Use% Mounted on

/dev/mapper/cl-root          xfs        50G  3.0G   48G   6% /

/dev/sda1                    xfs      1014M  179M  836M  18% /boot

/dev/mapper/cl-home xfs       965G   42G  924G   5% /home

Stop the service that might be using the partition that we are going to change

# systemctl stop elasticsearch

Rename the original directory to other name

# mv /var/lib/elasticsearch /var/lib/elasticsearch-old

Create a new directory to replace the one we already renamed above

# mkdir /var/lib/elasticsearch

Unmount /home

# umount /home

Check the name of volume group and logical volume

# lvs

Rename the logical volume to the one we desired. This is totally optional. You can use -t flag to test out the renaming process before proceeding

# lvrename -t cl home elasticsearch

# lvrename cl home elasticsearch

Change /etc/fstab to reflect on the new logical volume name and mount point. Test it out without the  -i option, before permanently make the change using the -i option

# sed 's/cl-home/cl-elasticsearch/g;s/\/home/\/var\/lib\/elasticsearch/g' /etc/fstab

# sed -i 's/cl-home/cl-elasticsearch/g;s/\/home/\/var\/lib\/elasticsearch/g' /etc/fstab

Mount it

# mount -a

Check to see if your new directory and logical volume mounted properly

# df -Th

Filesystem                   Type      Size  Used Avail Use% Mounted on

/dev/mapper/cl-root          xfs        50G  3.0G   48G   6% /

/dev/sda1                    xfs      1014M  179M  836M  18% /boot

/dev/mapper/cl-elasticsearch xfs       965G   42G  924G   5% /var/lib/elasticsearch

Move the content of /var/lib/elasticsearch to /home

# mv /var/lib/elasticsearch/* /home

Move the content of /var/lib/elasticsearch-old to /var/lib/elasticsearch

# mv /var/lib/elasticsearch-old/* /var/lib/elasticsearch

Remove /var/lib/elasticsearch-old

# rmdir /var/lib/elasticsearch-old

Set proper permission for /var/lib/elasticsearch

# chmod 750 -R /var/lib/elasticsearch

# chown -R elasticsearch.elasticsearch /var/lib/elasticsearch

Start your service

# systemctl start elasticsearch

Done.

Adding new virtual hard disk to existing RHV virtual machine

Login to your RHV/RHEV/ovirt console

Enter your administrator username and password



Once inside, search for your VM name

Scroll down, and choose Disk tab

Add details of your new virtual hard disk and click OK once done.



Make sure that your newly created disk is listed in the Disk tab

Login to your vm, and run lsblk to check your newly created disk
# lsblk 
NAME              MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
...
vdc               252:32   0   200G  0 disk 

Create partition on the new disk

# cfdisk /dev/vdc

Choose New --> Primary --> Set size --> Write --> answer 'yes' --> Quit

Run lsblk again to check if your partition is successfully created 

# lsblk 
NAME              MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
...
vdc               252:32   0   200G  0 disk 
└─vdc1            252:33   0   200G  0 part 



Make filesystem for your partition, in this case I want an ext4 partition
# mkfs.ext4 /dev/vdc1 
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
...
Writing superblocks and filesystem accounting information: done   

Once done, you can mount your partition wherever you want
# mount /dev/vdc1 /mnt
# df -Th /mnt/
Filesystem     Type  Size  Used Avail Use% Mounted on
/dev/vdc1      ext4  197G   61M  187G   1% /mnt

Score!!