Terminal display next month Calendar

When you use the cal command, you will see the current month and the current date selected, if you want to see the next month Calneder as well you can make use -A1 option along with the cal command.

mac ~ % cal -A1

    August 2021          September 2021     
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  
 1  2  3  4  5  6  7            1  2  3  4  
 8  9 10 11 12 13 14   5  6  7  8  9 10 11  
15 16 17 18 19 20 21  12 13 14 15 16 17 18  
22 23 24 25 26 27 28  19 20 21 22 23 24 25  
29 30 31              26 27 28 29 30

Similarly if you want to see forward 2 months use -A2

mac ~ % cal -A2

    August 2021          September 2021         October 2021      
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  
 1  2  3  4  5  6  7            1  2  3  4                  1  2  
 8  9 10 11 12 13 14   5  6  7  8  9 10 11   3  4  5  6  7  8  9  
15 16 17 18 19 20 21  12 13 14 15 16 17 18  10 11 12 13 14 15 16  
22 23 24 25 26 27 28  19 20 21 22 23 24 25  17 18 19 20 21 22 23  
29 30 31              26 27 28 29 30        24 25 26 27 28 29 30  
                                            31      

To see previous months you can use -B1, -B2, etc

mac % cal -B2

     June 2021             July 2021            August 2021       
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  
       1  2  3  4  5               1  2  3   1  2  3  4  5  6  7  
 6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14  
13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21  
20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28  
27 28 29 30           25 26 27 28 29 30 31  29 30 31