如何判断在shell程序命令行输入的程序参数$1是否为空
(2010-08-04 16:37:56)
转载▼标签： it |
本来一直使用：
DB_NAME=$1
if [ -z $DB_NAME ]
then
echo "database no selected yet "
DB_NAME=remotedb
else
echo "datebase selected yet "
echo "datebase selected yet DB_NAME=$DB_NAME"
fi
但是不能判断，一直显示不是空串，后面查询知道
问题跟用的shell有关。如果用ksh，直接用[ -z $1 ]或[[ -z $1 ]]就可以了，如果是sh，要把$1引起来：[ -z "$1" ]。另一个方法是[ ARG"$1" == ARG ]
修改为下面，OK了
DB_NAME=$1
if [ -z "$DB_NAME" ]
then
echo "database no selected yet "
DB_NAME=remotedb
else
echo "datebase selected yet "
echo "datebase selected yet DB_NAME=$DB_NAME"
fi
