Linux - Useful Commands for Linux Newbies - lsblk , cal , date

To list all the Block devices with their Mount points

#lsblk

The “lsblk” stands for (List Block Devices)

It lists  block devices by their assigned name in a tree-like fashion.


Example output

# lsblk

NAME                          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                             8:0    0  1.1T  0 disk
├─sda1                          8:1    0  200M  0 part /boot
├─sda2                          8:2    0   16G  0 part
│ └─VGswap-LVswap (dm-0)      253:0    0   16G  0 lvm  [SWAP]
└─sda3                          8:3    0  1.1T  0 part
  ├─VGdata-rootdir (dm-1)     253:1    0   17G  0 lvm  /
  ├─VGdata-usr6 (dm-2)        253:2    0   40G  0 lvm  /usr6
  ├─VGdata-usr7 (dm-3)        253:3    0   40G  0 lvm  /usr7
  ├─VGdata-usr4 (dm-4)        253:4    0   40G  0 lvm  /usr4
  ├─VGdata-usr5 (dm-5)        253:5    0   40G  0 lvm  /usr5
  ├─VGdata-usr2 (dm-6)        253:6    0   40G  0 lvm  /usr2
  ├─VGdata-usr3 (dm-7)        253:7    0   40G  0 lvm  /usr3
  ├─VGdata-usr1 (dm-8)        253:8    0   40G  0 lvm  /usr1
  ├─VGdata-home (dm-9)        253:9    0   20G  0 lvm  /home
  ├─VGdata-tmp (dm-10)        253:10   0   10G  0 lvm  /tmp
  ├─VGdata-tmpfs (dm-11)      253:11   0   10G  0 lvm  /tmpfs
  ├─VGdata-apps (dm-12)       253:12   0   25G  0 lvm  /apps
  ├─VGdata-var (dm-13)        253:13   0   10G  0 lvm  /var
  ├─VGdata-datadump (dm-14)   253:14   0  106G  0 lvm  /datadump
  ├─VGdata-coldbackup (dm-15) 253:15   0  197G  0 lvm  /coldbackup
  ├─VGdata-undo (dm-16)       253:16   0   30G  0 lvm  /undo
  ├─VGdata-index2 (dm-17)     253:17   0   40G  0 lvm  /index2
  ├─VGdata-index3 (dm-18)     253:18   0   40G  0 lvm  /index3
  ├─VGdata-index1 (dm-19)     253:19   0   40G  0 lvm  /index1
  ├─VGdata-arch (dm-20)       253:20   0  119G  0 lvm  /arch
  ├─VGdata-index4 (dm-21)     253:21   0   40G  0 lvm  /index4
  ├─VGdata-temp (dm-22)       253:22   0   30G  0 lvm  /temp
  ├─VGdata-redo5 (dm-23)      253:23   0 1008M  0 lvm  /redo5
  ├─VGdata-redo4 (dm-24)      253:24   0 1008M  0 lvm  /redo4
  ├─VGdata-redo1 (dm-25)      253:25   0 1008M  0 lvm  /redo1
  ├─VGdata-redo3 (dm-26)      253:26   0 1008M  0 lvm  /redo3
  └─VGdata-redo2 (dm-27)      253:27   0 1008M  0 lvm  /redo2
sr0                            11:0    1 1024M  0 rom


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The “cal” (Calendar), it is used to displays calendar of the present month or any other month of any year that is advancing or passed.

# cal

# cal
    February 2016
Su Mo Tu We Th Fr Sa
    1  2  3  4  5  6
 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29
Calender of February 1971

# cal 02 1971

    February 1971
Su Mo Tu We Th Fr Sa
    1  2  3  4  5  6
 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28
Calender of February 2050

# cal 02 2050
    February 2050
Su Mo Tu We Th Fr Sa
       1  2  3  4  5
 6  7  8  9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28
--------------------


The “date” (Date) command print the current date and time on the standard output, and can further be set.

# date
Wed Feb 24 13:16:54 IST 2016
To set the date

# date --set='24 feb 2016 13:14'