What directory is '~' when I type 'cd

2019-02-18 07:26发布

I'm only new to using SSH, but when I log in I end up in the directory ~, which in general is the same directory when FTPing in. I can still go to /, but I don't know what the ~ means. Home? Where is it in relation to /, or how could I find out?

11条回答
来,给爷笑一个
2楼-- · 2019-02-18 07:34

~ is an alias to the currently logged in users home directory. To find out where that really is, type pwd (stands for: Print Working Directory) right after logging in, which should give you the location relative to /. It's probably something like:

/home/myusername
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啃猪蹄的小仙女
3楼-- · 2019-02-18 07:34

~ is your home directory. To see the path type:

echo ~

in the terminal

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老娘就宠你
4楼-- · 2019-02-18 07:36

Different shells may or may not handle this differently, but Johnathan got the closest without coming out and saying it. The shell expands "~" to whatever's stored in the $HOME environment variable. The shell expands ~username to whatever's listed in the shell field of /etc/passwd for the given username. If you don't override it, the shell (or ssh, depending on the implementation) will set $HOME to be the home field from /etc/passwd, so they're both the same (assuming you're "username") until you change one.

As to why you see a ~ in ssh...

The prompt says "~" is your current directory most likely because you're using Bash as your shell, and the value of $PS1 (the prompt string you see - it's set in /etc/profile or /etc/profile.d/*, more than likely) contains a \w or a \W somewhere. The \w string in the prompt shows the current directory, and collapses to a "~" when you're in the directory specified by $HOME. Here's a little demo starting in my homedir - note how the "\w" gets replaced with either the current directory or with a ~, based on what the value of HOME is set to. Also note that the trailing slash doesn't work - HOME can't end with a slash for this to work. :)

danny@machine ~ > export PS1='\w > '     # change my prompt (effective on next line)
~ > cd /tmp                              # move to /tmp to demonstrate
/tmp > export HOME=/tmp/                 # set HOME to include trailing /
/tmp > export HOME=/tmp                  # try again without trailing /
~ >                                      # notice that this works
~ > cd /home/danny                       # back to homedir
/home/danny > export HOME=/home/danny    # see how it's /home/danny, not ~
~ > export PS1='danny@machine \w > '     # after resetting $HOME, it should work ok
danny@machine ~ >                        # hooray!
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Summer. ? 凉城
5楼-- · 2019-02-18 07:37

Home directory need not necessarily be under /home as kigurai has pointed out.

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冷血范
6楼-- · 2019-02-18 07:38

You can try realpath

realpath ~
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三岁会撩人
7楼-- · 2019-02-18 07:38

~ expands to your home directory, as has been pointed out, but I think it's worth noting that isn't a feature of ssh itself.

ssh (among many other wonderful features!) lets you establish a remote shell, and this shell can provided by many different pieces of software.

On a *nix system, your account will be associated with a particular shell, GNU bash is a popular choice. And it so happens than in bash, and most other POSIX compliant shells, the tilde character expands as a shortcut to your home directory.

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