（4）编写一个shell脚本month.sh，以英文月份名为参数，显示当年该月的日历。

Sure, I can help you with that! Here's a simple shell script called `month.sh` that takes an English month name as input and displays the calendar for that month:

#!/bin/bash

# Check if the argument is provided and valid
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <month_name>"
    exit 1
fi

month="$1"
case $month in
    January|February|March|April|May|June|July|August|September|October|November|December)
        cal "$month"  # Use 'cal' command to display the calendar
        ;;
    *)
        echo "Invalid month name. Please enter one of the following: January, February, March, April, May, June, July, August, September, October, November, December."
        exit 1
        ;;
esac

exit 0

To use this script, save it to a file named `month.sh`, make it executable by running `chmod +x month.sh`, and then run it followed by a month name like this:

./month.sh January

This will output the calendar for January.