“/bin/bash cd ~”导致“/bin/bash: cd: No such file or directory”，为什么？
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"/bin/bash cd ~" results in "/bin/bash: cd: No such file or directory", why?
提问by Andy
The question is in the title. I could not find anything on google, so im hoping someone here can explain this to me.
问题在标题中。我在谷歌上找不到任何东西，所以我希望这里有人可以向我解释这一点。
I am using debian 6.0.5 and the shell assigned to the executing user in the /etc/passwd file is /bin/bash
我使用的是 debian 6.0.5，在 /etc/passwd 文件中分配给执行用户的 shell 是 /bin/bash
So, simply writing cd ~works and brings me to the users home directory.
因此，只需编写cd ~作品并将我带到用户主目录。
test -d "~/some_dir"returns false in an if statement ( some_dir exsits )
test -d "~/some_dir"在 if 语句中返回 false ( some_dir exsits )
Edit:
Sorry I should've been more clear as of why I was writing /bin/bash cd ~instead of cd ~: I am writing a bash script with #!/bin/bashand the above mentioned if statement ends up in the false clause.
编辑：对不起，我应该更清楚为什么我要写/bin/bash cd ~而不是cd ~：我正在写一个 bash 脚本，#!/bin/bash上面提到的 if 语句以 false 子句结尾。
回答by Benjamin Bannier
Assuming you did
假设你做了
$ /bin/bash cd ~
your shell interpreted cdas an argument to /bin/bash. That syntax can e.g. be used to invoke shell scripts.
您的 shell 被解释cd为/bin/bash. 例如，该语法可用于调用 shell 脚本。
What you most likely wanted was to change the current working directory. In that case all you need is
您最有可能想要的是更改当前工作目录。在这种情况下，您只需要
$ cd ~
回答by francoisrv
Try the following:
请尝试以下操作：
/bin/bash -c "cd ~"
回答by ghoti
The options for any command line are expanded before the command is run, even for internal commands. Whatever shell you're using to run /bin/bash cd ~is presumably interpreting the tilde literally rather than a special character that expands to your home directory.
任何命令行的选项都会在命令运行之前展开，即使对于内部命令也是如此。无论您使用什么 shell 来运行/bin/bash cd ~，大概都是按字面解释波浪号，而不是扩展到主目录的特殊字符。
As a test, try creating a directory by that name and see if the error goes away.
作为测试，尝试使用该名称创建一个目录，然后查看错误是否消失。
> mkdir ./~
> /bin/bash cd ~
Note that the cdcommand needs to be done within your running shellto be useful. When you change the working directory of a sub-shell, and then the sub-shell exits, you'll find yourself back where you started.
请注意，该cd命令需要在您正在运行的 shell 中完成才能有用。当您更改子 shell 的工作目录，然后子 shell 退出时，您会发现自己回到了开始的地方。
UPDATE:
更新：
From within a bash script, you should be able to use the $HOMEenvironment variable, which should consistently contain your home directory. I'm not aware what conditions would cause tilde expansion to fail, but I've always used $HOME.
在 bash 脚本中，您应该能够使用$HOME环境变量，它应该始终包含您的主目录。我不知道什么条件会导致波浪号扩展失败，但我一直使用$HOME.
Also, when determining whether you can change into a particular directory, you have the option of being explicit and returning useful status:
此外，在确定是否可以更改到特定目录时，您可以选择明确并返回有用的状态：
unset err
if [[ ! -d "$somedir" ]]; then
err="Can't find $somedir"
elif [[ ! -r "$somedir" ]]; then
err="Can't read $somedir"
fi
if [[ -n "$err" ]]; then
echo "$ERROR: $err" >&2
exit 1
fi
cd "$somedir"
Or, you can just try the CD and look at its results.
或者，您可以尝试 CD 并查看其结果。
if ! cd "$somedir"; then
echo "ERROR: $somedir not availble"
exit 1
fi
Detailed error reports are handy, but if you don't need them, keeping your code small has advantages as well.
详细的错误报告很方便，但如果您不需要它们，保持代码小也有好处。
回答by Federico
Do not use quotes ""Example:
不要使用引号""示例：
$ test -d ~/.aptitude
$ echo $?
0
$ test -d "~/.aptitude"
$ echo $?
1
~is not expanded within the quotes "". Use $HOME
~没有在引号内展开""。用$HOME
