linux - 如果 bash 脚本的条件有什么问题

Question

我有安装了 ZSH 的 Ubuntu 18.04。我有这个 bash 脚本用于检查目录是否存在。

即使我有一个名为“~/.config”的目录，条件始终为负。我似乎无法弄清楚我的代码有什么问题。

setup.sh

#!/bin/bash

if [ -d "~/.config" ] ; then
  echo "Directory exist"
else
  echo "Does not exist"
fi

使用 chmod +x ./setup.sh 使文件可执行 输出总是不存在

Answer 1

由于您编写了 "~/.config"，它将被视为文字字符串。为了允许 ~ shell 扩展，你需要不加引号:

#!/bin/bash
if [ -d ~/.config ] ; then
  echo "Directory exist"
else
  echo "Does not exist"
fi

Bash Pitfals, 26. echo "~" 很好地解释了这一点:

26. echo "~"

Tilde expansion only applies when '~' is unquoted. In this example echo writes '~' to stdout, rather than the path of the user's home directory.

Quoting path parameters that are expressed relative to a user's home directory should be done using $HOME rather than '~'. For instance consider the situation where $HOME is "/home/my photos".

"~/dir with spaces" # expands to "~/dir with spaces"
~"/dir with spaces" # expands to "~/dir with spaces"
~/"dir with spaces" # expands to "/home/my photos/dir with spaces"
"$HOME/dir with spaces" # expands to "/home/my photos/dir with spaces"`