mjhjmtu

How is a filesystem identified or specified? Some commands such as resize2fs expect a filesystem as an argument. The mount directory of a file system doesn't work.

Does name such as /dev/sda3 identify/specify a partition or a filesystem? I thought that /dev/sda3 specifies/identifies a partition (as seen in the output of fdisk -l), instead of a filesystem, but it works as a filesystem argument to resize2fs.

Generally, are partition and filesystem specified and identified in the same ways?

Thanks.

$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 3.9G 0 3.9G 0% /dev
tmpfs 788M 1.5M 786M 1% /run
/dev/sda3 260G 16G 231G 7% /
tmpfs 3.9G 542M 3.4G 14% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/sda4 550G 323G 199G 62% /home
tmpfs 788M 52K 788M 1% /run/user/1000
tmpfs 788M 4.0K 788M 1% /run/user/1001

$ sudo fdisk -l
Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 

Device Start End Sectors Size Type
/dev/sda1 2048 4095 2048 1M BIOS boot
/dev/sda2 4096 31254527 31250432 14.9G Linux swap
/dev/sda3 1398441984 1953523711 555081728 264.7G Linux filesystem
/dev/sda4 226566144 1398441983 1171875840 558.8G Linux filesystem

Partition table entries are not in disk order.

$ sudo parted -l
Model: ATA ST1000LM014-1EJ1 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number Start End Size File system Name Flags
 1 1049kB 2097kB 1049kB bios_grub
 2 2097kB 16.0GB 16.0GB linux-swap(v1)
 4 116GB 716GB 600GB ext4
 3 716GB 1000GB 284GB ext4