如果脚本有
if [ $1 == "-?" ]; then #line 4 echo "usage: ...." fi
当脚本在没有任何参数的情况下运行时,它会抱怨
./script.sh: line 4: [: ==: unary operator expected
但如果相反
if [ "$1" == "-?" ]; then #line 4 echo "usage: ...." fi
一切都很好
这是为什么?
谢谢