<span class="Apple-style-span" style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">在学习bash编程时遇到的问题</span><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">

讲解中提示bash脚本中</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">-n 当字符串不为空时为真</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">-z 当字符串为空时为真</div>

<div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">那么以下脚本</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">

str=""</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">if [ -n $str ]</div>

<div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">then</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">echo "1"</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">

fi</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">if [ -z $str ]</div>
<div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
then</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">echo "2"</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">fi</div>

<div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">执行时会输出</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">

1</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">2</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">为什么会两个都输出呢？</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">

str为空同时也不为空？？</div><div style="font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">还是我理解有误或者设置有误？？</div>————<br>如果说我们是浪漫主义者，是不可救药的理想主义分子，我们想的都是不可能的事情，那么，我们将一千零一次的回答，是的，我们就是这样的人。忠于理想，面对现实。<br><div>

<font face="'times new roman', serif" size="1"><br></font></div><div><font face="'times new roman', serif" size="1"><a href="http://goo.gl/5liFC" target="_blank">若为自由故，需有过墙梯</a></font></div><br>