bash的条件语句：如何＆QUOT;和＆QUOT;前pressions？ （如果[-z $ VAR和放大器;！＆安培; -e $ VAR]） [英] bash conditionals: how to "and" expressions? (if [ ! -z $VAR && -e $VAR ])

问题描述

我想我不是如何做和试验清楚。我想，以确保存在的参数，它与运行良好[-e $ VAR] ，但事实证明，也被评估对空字符串为真;我不想要的。

我如何'和'在一起？还是有另一种一元的测试完成我想要什么？

解决方案

 如果[！ -z$ VAR]放;＆安培; [-e$ VAR];然后
      ＃东西...
科幻
 

I guess I'm not clear on how to do "and" tests. I wanted to make sure an argument existed which was working well with [ -e $VAR ] but turns out that was also evaluating as true on empty string; which I do not want.

How do I 'and' them together? Or is there another unary test that accomplishes what I want?

解决方案

if [ ! -z "$var" ] && [ -e "$var" ]; then
      # something ...
fi

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