Michael Mao Michael Mao - 4 months ago 10
Bash Question

bash - how to pipe result from the which command to cd

I know this must be a stupid question, but how could I pipe the result from a which command to cd?

This is what I am trying to do:

which oracle | cd
cd < which oracle


But none of them works :(

Is there a way to achieve this (rather than copy/paste of course)?

Thanks a lot in advance!

Edit : on second thought, this command would fail, because the destination file is NOT a folder/directory.

So I am thinking and working out a better way to get rid of the trailing "/oracle" part now (sed or awk, or even Perl) :)

Edit :
Okay that's what I've got in the end:


cd `which oracle | sed 's/\/oracle//g'`

Answer

You use pipe in cases where the command expects parameters from the standard input. ( More on this ).

With cd command that is not the case. The directory is the command argument. In such case, you can use command substitution. Use backticks or $(...) to evaluate the command, store it into variable..

path=`which oracle`
echo $path # just for debug
cd $path

although it can be done in a much simpler way:

cd `which oracle` 

or if your path has special characters

cd "`which oracle`"

or

cd $(which oracle)

which is equivalent to backtick notation, but is recommended (backticks can be confused with apostrophes)

.. but it looks like you want:

cd $(dirname $(which oracle))

(which shows you that you can use nesting easily)

$(...) (as well as backticks) work also in double-quoted strings, which helps when the result may eventually contain spaces..

cd "$(dirname $(which oracle))"