showing cal command in linux not found code example

Example: unix format calendar

cal -n 3
   September 2016         October 2016
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
          1  2  3  4                  1  2
 5  6  7  8  9 10 11   3  4  5  6  7  8  9
12 13 14 15 16 17 18  10 11 12 13 14 15 16
19 20 21 22 23 24 25  17 18 19 20 21 22 23
26 27 28 29 30        24 25 26 27 28 29 30
                      31