Write a shell script to modify “cal” command to display calendars of the specified months.

 Write a shell script to modify “cal” command to display calendars of the specified months.

CODE:

#!/bin/bash

# Check if at least one argument is provided

if [ $# -eq 0 ]; then

    echo "Usage: $0 <month1> [month2 month3 ...]"

    exit 1

fi

# Loop through each provided month and display the calendar

for month in "$@"; do

    # Check if the input is a valid month number (1-12)

    if ! [[ $month =~ ^[1-9]|1[0-2]$ ]]; then

        echo "Invalid month number: $month. Month should be between 1 and 12."

        exit 1

    fi

    # Display the calendar for the specified month

    cal $month

    echo "------------------------------------------"

done

Save this script in a file, for example, custom_cal.sh, and make it executable:

chmod +x custom_cal.sh

You can then run the script by providing one or more month numbers as command-line arguments:

./custom_cal.sh 1 3 7

OUTPUT:

    January 2023      

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 30 31              

------------------------------------------

     March 2023       

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 30 31     

------------------------------------------

      July 2023       

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  

30 31                

------------------------------------------