我一直在试图弄清楚这是什么问题，但只是不能算出来。
这是部分似乎得到一个错误..
elif [ $operation = "man" ]; then
if [ $aug1 = "add" ]; then # <- Line 75
echo "Man Page for: add"
echo ""
echo "Syntax: add [number 1] [number 2]"
echo ""
echo "Description:"
echo "Add two different numbers together."
echo ""
echo "Info:"
echo "Added in v1.0"
echo ""
elif [ -z $aug1 ]; then
echo "Please specify a command to read the man page."
else
echo "There is no manual page for that command."
fi
我得到这个错误：
calc_1.2: line 75: [: =: unary operator expected
