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cd –, a shell feature I didn't know about

7 points by sandreas ↗ HN
Recently, someone submitted a pull request to one of my projects, which included a shell feature, i always wanted to have, but didn't know it exists. The project includes a little build script, which changes the directory, executes some commands and then changes back to the original directory, where it came from.

To achieve this, i used the "pushd" and "popd" command, which unfortunately seems not to be available on every POSIX platform. So, as an alternative, the pull request included:

  cd -
which i never came across and which surprisingly (at least for me) did the same thing... Further research lead me to following information:

"cd -" expands the "-" to $OLDPWD, which, as the name intends, points to the directory visited before. Using this variable results in a history size of 1, so you can only switch between the last and the current directory, but in most cases, that should be enough.

Then I immediately thought of a problem... how to change to a directory named "-"? Well, heres the answer:

  cd ./-
Now that I know about it, I use it nearly every day.

Have fun!

5 comments

[ 2.9 ms ] story [ 26.9 ms ] thread
azeirah
Ahh yeah cd - is super useful once you know it.

A similar one is

!!

For example

    apt install python3
And you forgot sudo, whoops

    sudo !!
!! will be replaced by the last command you executed.

Or

    /etc/logs/apache2/error.log
Oh whoops, forgot cat/vim/less/tail/whatever

    vim !!
Etc
sandreas
Cool... next thing on my cheatsheet. Thanks.
emrox
also available on git

  git checkout master
  git checkout my-branch
  git pull
  git checkout -
  git merge -
oddly
Here are some more useful shell bits. - When prefixing a command with a space, it is not logged in the history. - !$ represents the argument of the previous command. $_ should also work.