wholenum

来自「UNIX+shell范例精解（第4版）代码」· 代码 · 共 13 行

#!/bin/sh
# Name:wholenum
# Purpose:The expr command tests that the user enters an integer
echo "Enter a number."
read number
if expr "$number" + 0 > /dev/null 2>&1
then
	:
else
	echo "You did not enter an integer value."
	exit 1
fi