Warning: If you run fdisk on the wrong drive here or there is some important data left, you might lose all your data and it will be very hard to restore. Before running these commands, triple-check that you’ve used the correct device (e.g. /dev/sdh)!
In order to create a partition table on a device (e.g. /dev/sdh – /dev/sdh1 is not a device but a partition, so using that does not make any sense!), run these commands
sudo fdisk <device file>
If the device doesn’t have a valid partition table, fdisk will automatically create a partition table (but not write it to the disk yet). It will show this output if that is the case (the identifier is random and different every time):
Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x81ee11ff.
Command (m for help):
If you are sure that you want to run the partition, enter w and press return to write the partition table to disk & exit.
The partition table will be effective immediately, but will not contain any partition. In order to create a partition (for this example we will create one partition being as large as the entire device), run
sudo fdisk <device file>
again.
This time, enter the n command (new partition). When it asks you about the partition type and its size, just press return every time to select the defaults. It should look like this (<return> added to show you where you should press return).
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): <return>
Partition number (1-4, default 1): <return>
First sector (2048-31143935, default 2048): <return>
Last sector, +sectors or +size{K,M,G,T,P} (2048-31143935, default 31143935): <return>After that, when fdisk prompts for a command again (i.e. when it says Command (m for help): ), enter w in order to write the changes (i.e. the new partition) to the disk & exit. After fdisk exits, you can see the partition in /dev, e.g. /dev/sdh1
After that, you’ll likely need to create a filesystem on that partition, e.g. sudo mkfs.ext4 /dev/sdh1 or sudo mkfs.vfat /dev/sdh1 . Make sure to create the correct filesystem for the operating system and usecase the device will be used in.
