Two new ls command learned today.

#2: lsblk

Use this command to list block devices
# lsblk 
Sample outputs:

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    1  68.3G  0 disk
├─sda1   8:1    1   716M  0 part /boot
├─sda2   8:2    1     8G  0 part [SWAP]
└─sda3   8:3    1  59.6G  0 part /
sr0     11:0    1  1024M  0 rom

To see file system type:
# lsblk -f
Sample outputs:

NAME   FSTYPE LABEL MOUNTPOINT
sda
├─sda1 ext2         /boot
├─sda2 swap         [SWAP]
└─sda3 ext4         /
sr0

To output info about permissions:
# lsblk -m
Sample outputs:

NAME     SIZE OWNER GROUP MODE
sda     68.3G root  disk  brw-rw----
├─sda1   716M root  disk  brw-rw----
├─sda2     8G root  disk  brw-rw----
└─sda3  59.6G root  disk  brw-rw----
sr0     1024M root  cdrom brw-rw----

#3: lsb_release

Use this command to see Linux distribution-specific information, enter:
# lsb_release
# lsb_release -a
Sample outputs:

LSB Version: :core-4.0-amd64:core-4.0-ia32:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-ia32:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 5.8 (Final)
Release: 5.8
Codename: Final