how to see drives in centos 7 code example

Example 1: list all hard drives linux

user@system:~$ fdisk -l
 Disk /dev/loop0: 7.5 MiB, 7811072 bytes, 15256 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes

 Disk /dev/loop1: 89.5 MiB, 93818880 bytes, 183240 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disk /dev/loop2: 4.9 MiB, 5148672 bytes, 10056 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disk /dev/loop3: 4.7 MiB, 4919296 bytes, 9608 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disk /dev/loop4: 89.5 MiB, 93835264 bytes, 183272 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disk /dev/loop5: 88.2 MiB, 92483584 bytes, 180632 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disk /dev/sda: 477 GiB, 512110190592 bytes, 1000215216 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 
 Disklabel type: gpt
 Disk identifier: 129F4EE6-2A54-4639-BFCA-2CC09DFC8566
 Device       Start        End   Sectors   Size Type
 /dev/sda1     2048    1050623   1048576   512M EFI System
 /dev/sda2  1050624 1000214527 999163904 476.4G Linux filesystem

Example 2: list all hard drives linux

user@system:~$ df -h
 Filesystem      Size   Used  Avail  Use%  Mounted on
 udev             7.8G     0   7.8G    0%  /dev
 tmpfs            1.6G   3.5M   1.6G    1%  /run
 /dev/sda2        468G   204G   242G   46%  /
 tmpfs            7.8G   109M   7.7G    2%  /dev/shm
 tmpfs            5.0M   4.0K   5.0M    1%  /run/lock
 tmpfs            7.8G     0   7.8G    0%  /sys/fs/cgroup
 /dev/loop0       7.5M   7.5M    0  100%  /snap/canonical-livepatch/54
 /dev/loop1       90M    90M     0  100%  /snap/core/6034
 /dev/loop2       5.0M   5.0M    0  100%  /snap/canonical-livepatch/50
 /dev/loop4       90M    90M     0  100%  /snap/core/6130
 /dev/loop3       4.8M   4.8M    0  100%  /snap/canonical-livepatch/49
 /dev/loop5       89M    89M     0  100%  /snap/core/5897
 /dev/sda1        511M   6.1M   505M   2%  /boot/efi
 tmpfs            1.6G    16K   1.6G    1%  /run/user/121
 tmpfs            1.6G    44K   1.6G    1%  /run/user/1000