How to view unallocated free space on a hard disk through terminal [closed]

I want to view the unallocated free space on my hard disk through terminal. I've burned my brains searching the internet for a possible solution, but all in vain.

I used all sorts of commands like df, du, fdisk, parted, etc. It tells me about the disks that are mounted and unmounted, but what about the unallocated space that I've left free?

Of course I can view it using the 'Disk Utility' app provided by Fedora, but since I LOVE being in the terminal I'd like to view in it.

Can anyone please help me with a solution?

Solution 1:

Use GNU parted and print free command:

root@sandbox:~# parted
GNU Parted 2.3
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print free
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 64.4GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type      File system  Flags
        32.3kB  1049kB  1016kB            Free Space
 1      1049kB  256MB   255MB   primary   ext2         boot
        256MB   257MB   1048kB            Free Space
 2      257MB   64.4GB  64.2GB  extended
 5      257MB   64.4GB  64.2GB  logical                lvm
        64.4GB  64.4GB  1049kB            Free Space

Solution 2:

To see in TB:

# parted /dev/sda unit TB print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

To see in GB:

# parted /dev/sda unit GB print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

To see in MB:

# parted /dev/sda unit MB print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

To see in bytes:

# parted /dev/sda unit B print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

To see in %:

# parted /dev/sda unit '%' print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

To see in sectors:

# parted /dev/sda unit s print free | grep 'Free Space' | tail -n1 | awk '{print $3}'

Change /dev/sda to whatever device you are trying to find the information about. If you are using the result in any calculations, make sure to trim the trailing characters.

Solution 3:

In addition to all the answers about how to find unpartitioned space, you may also have space allocated to an LVM volume but not actually in use. You can list physical volumes with the pvdisplay and see which volume groups each physical volume is associated with. If a physical volume isn't associated with any volume group, it's safe to reallocate or destroy. Assuming that it it is associated with a volume group, the next step is to use vgdisplay to show your those. Among other things, this will show if you have any free "physical extents" — blocks of storage you can assign to a logical volume. You can get this in a concise form with vgs:

$ sudo vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  fedora   1   3   0 wz--n- 237.46g    0 

... and here you can see I have nothing free. If I did, that last number would be bigger than zero.

This is important, because that free space is invisible to du, df, and the like, and also will show up as an allocated partition if you are using fdisk or another partitioning tool.