Bdtyktl

maybe this is a simple thing but I have the following doubt.

If I perform fdisk -l, in the output I can find these devices that represent 2 partitions on the /dev/sdb device that is my SD card:

Dispositivo Boot      Start         End      Blocks   Id  System

/dev/sdb1            8192      122879       57344    c  W95 FAT32 (LBA)

/dev/sdb2          122880    15523839     7700480   83  Linux

From this output can I know is these partitions are mounted or unmounted ? (I think no).

What can I do to know if a specific partition is mounted on my system?

The mount command is the usual way. On Linux, you can also check /etc/mtab, or /proc/mounts.

You can also use df, which will give you a nicer printout and show the disk usage of the mounted file systems:

$ df -h

Filesystem      Size  Used Avail Use% Mounted on

/dev/sda3        27G  8.6G   17G  35% /

dev             2.0G     0  2.0G   0% /dev

run             2.0G  488K  2.0G   1% /run

tmpfs           2.0G  456K  2.0G   1% /dev/shm

tmpfs           2.0G     0  2.0G   0% /sys/fs/cgroup

tmpfs           2.0G  738M  1.3G  38% /tmp

/dev/sdb2       715G  515G  164G  76% /home

tmpfs           396M  4.0K  396M   1% /run/user/1000

lsblk is a nice way for humans to see devices and mount-points. See also this answer.

$ lsblk

NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT

sda               8:0    0   7.3T  0 disk

└─dataGB-dataVB 253:1    0  14.6T  0 lvm  /mnt/dataB

sdb               8:16   0   7.3T  0 disk

└─dataGB-dataVB 253:1    0  14.6T  0 lvm  /mnt/dataB

sdc               8:32   0   7.3T  0 disk

└─sdc1            8:33   0   7.3T  0 part

  └─dataG-data  253:0    0   7.3T  0 lvm  /mnt/data

sdd               8:48   0   7.3T  0 disk

└─sdd1            8:49   0   7.3T  0 part

sde               8:64   0   9.1T  0 disk

└─sde1            8:65   0   9.1T  0 part /mnt/dataC

nvme0n1         259:0    0 232.9G  0 disk

└─nvme0n1p1     259:1    0 232.9G  0 part /

findmnt is useful for scripting or to query a specific device:

$ findmnt /dev/sde1

TARGET     SOURCE    FSTYPE OPTIONS

/mnt/dataC /dev/sde1 xfs    rw,relatime,attr2,inode64,noquota

I suppose you could use the command blkid to list what is mounted (DQMOT). I would suggest setting up your sudo gedit /etc/fstab - if you didn't know of it - with the outputs for the hard drives blkid picks up. The UUIDs "universally unique identifier" are a better way of mounting than other methods.

For example:

# <file system> <mount point>                   <type>  <options>                      <dump>  <pass>

UUID=9ee10f9f-c7fa-4c94-93dc-d8ca02db9c2f /     ext4    errors=remount-ro              0       1

UUID=48ee8-657-3154044569-d52005b00ded-68 none  swap    sw                             0       0

UUID=C8CE6F14CE6EF9D8 /media/john/windows       ntfs    defaults                       0       0

UUID=F4644D2D644CF3C0 /media/john/e             ntfs    defaults                       0       0

You can also often see in the file manager GUI: win+e and look at whether or not the disks are mounted with the up-turned arrows. You can also mount/un-mount from this menu.

The simplest way is use the command mount:

 $ mount

 /dev/sda1 on / type ext4 (rw,errors=remount-ro)

 proc on /proc type proc (rw,noexec,nosuid,nodev)

 sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)

 none on /sys/fs/cgroup type tmpfs (rw)

 none on /sys/fs/fuse/connections type fusectl (rw)

 none on /sys/kernel/debug type debugfs (rw)

 none on /sys/kernel/security type securityfs (rw)

 udev on /dev type devtmpfs (rw,mode=0755)

 devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)

 tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)

 none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)

 none on /run/shm type tmpfs (rw,nosuid,nodev)

 none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755)

 none on /sys/fs/pstore type pstore (rw)

 /dev/sda6 on /home type ext4 (rw)

 binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)

 rpc_pipefs on /run/rpc_pipefs type rpc_pipefs (rw)

 systemd on /sys/fs/cgroup/systemd type cgroup (rw,noexec,nosuid,nodev,none,name=systemd)

This information is stored in /etc/mtab, you can see by yourself that the output of mount is nearly identical to that of /etc/mtab

How about gnome-disks? Depending on the Ubuntu release, it appears in classic menus as Disks under either Accessories or Utilities?

It gives a graphical map of each disc unit and full details of device name, size, mount status, etc, and also allows mount/dismount. It has the advantage over mount of showing both mounted and unmounted partitions, but as a GUI program it does not have an output that can be piped to other processes in a script. Unlike blkid it does not need root priveleges.