if与字符串表达式 #
字符串表达式常见的有以下几种
| 表达式 | 含义 |
|---|---|
| -z | 字符串长度为0 |
| -n | 字符串长度不为0 |
脚本说明
#!/bin/bash
answer="wangteng"
if [ -z "${answer}" ];then
echo "there is no answer."
exit 1
fi
if [ "$answer" == "ab" ];then
echo "the answer is incorrect"
elif [ "$answer" == "cd" ];then
echo "the answer is also incorrect."
elif [ "$answer" == "wangteng" ];then
echo "the answer is correct."
else
echo "the answer is unknown."
fi