So I know that pwd
and cd
in the shell have a "logical" and "physical" mode (see this SO question and questions linked from there).
Now, assume I have this symlink:
/home/<username>/foo -> /tmp/bar
To follow along locally, just do this:
mkdir /tmp/bar
ln -s /tmp/bar ~/foo
Now, when I start in my $HOME
and cd
into foo
, I get the "logical" path (with default settings) with pwd
, and can get the "physical" path with -P
:
$ cd ~/foo
$ pwd
/home/<username>/foo
$ pwd -P
/tmp/bar
Of course, "..
" always refers to the parent of the "physical" path (my understanding is that it is not even interpreted by the shell, just passed to the command as-is, and some special built-in commands like cd
interpret it specially to get the "logical" behavior):
$ pwd
/home/<username>/foo
$ realpath ..
/tmp
What I want is when I'm in $HOME/foo
(or any of its subdirectories) that any relative paths I use (e.g. ls -l ../..
) to be interpreted/expanded relative to the "logical" path (it's fine if I have to prefix my command with something).
For example:
$ pwd
/home/<username>/foo
$ vi ../something.txt
I want this to resolve to vi /home/<username>/something.txt
.
Is there something easier/shorter than doing the following (or writing a shell function that I can prefix my command with that goes over all arguments and – if they refer to paths – expand them before passing them to the command)?
$ pwd
/home/<username>/foo
$ realpath -L $PWD/../something.txt
/home/<username>/something.txt
$ vi $(realpath -L $PWD/../something.txt)
Is there something like a "logical path expansion for command line parameters that are relative file paths being done before the shell executes the command"? I'm using zsh
, but any solutions for bash
or zsh
would be fine.
Best Answer
I'll answer this for Zsh, since that's what I'm using.
To get the effect you want with
..
when usingcd
, simply add the following to your~/.zshrc
file:Documentation here: http://zsh.sourceforge.net/Doc/Release/Options.html#index-CHASEDOTS
For all other cases, instead of
..
, you will need to use the:h
("head") expansion modifier:If you need to reach up more than one level, you can append a number to it (provided you surround the expression with curly braces) or just repeat the
:h
:Documentation here: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Modifiers