如果[-e file.txt]在bash中不起作用 [英] `if [-e file.txt]` not working in bash

问题描述

我正在尝试使用bash检查文件是否存在.这是我的代码

I'm trying to check if a file exists using bash. This is my code

if [-e file.txt]; then
  echo "file exists"
else
  echo "file doesn't exist"
fi

但是当我运行它时，我得到:

But when I run it I get:

./test.sh: line 3: [-e: command not found

我在做什么错了?

推荐答案

[在Bash中不是特殊标记；只是 word [是内置命令(就像echo一样).因此，您需要在其后留一个空间.而且，类似地，您在]之前需要一个空格:

[ is not a special token in Bash; it's just that the word [ is a builtin command (just like echo). So you need a space after it. And, similarly, you need a space before ]:

if [ -e file.txt ] ; then

也就是说，我建议使用[[ ]]而不是—在某些方面更安全(尽管仍然需要空格):

That said, I recommend [[ ]] instead — it's safer in a few ways (though it still requires the spaces):

if [[ -e file.txt ]] ; then

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