cd `dirname `which prog``

mzh · 05-02-2011, 04:04 AM

Hey guys,
I'm trying to remember how to use the output of a nested Bash builtin call.
So `which prog` gives me the path to the program, i'm interested in.
Then I would like to get the directory path leading to that program and plug it into 'cd', so i end up in the directory containing the program.

What am I missing?

thanks for any hints.

colucix · 05-02-2011, 04:10 AM

The syntax for command substitution that uses back ticks, does not permit nesting. Use the $(command) syntax instead:

Code:

cd $(dirname $(which prog))

Hope this helps.

mzh · 05-02-2011, 05:36 AM

Quote:

Originally Posted by colucix

The syntax for command substitution that uses back ticks, does not permit nesting. Use the $(command) syntax instead:

Code:

cd $(dirname $(which prog))

Hope this helps.

+1 for this.
Thanks.

MTK358 · 05-02-2011, 10:26 AM

Quote:

Originally Posted by colucix

The syntax for command substitution that uses back ticks, does not permit nesting.

It actually does, but the syntax is really ugly. But I also strongly recommend $() over backticks.

Telengard · 05-02-2011, 10:46 AM

Quote:

Originally Posted by MTK358

It actually does, but the syntax is really ugly. But I also strongly recommend $() over backticks.

For those like me who have to know.

Code:

word_count=` wc -w \`echo * | awk '{print $8}'\` `

http://www.tldp.org/LDP/abs/html/com...ml#FTN.AEN7219

David the H. · 05-02-2011, 10:52 AM

The Why is $(...) preferred over `...` (backticks)? FAQ page details the differences between the two forms, including complications with nesting, escaping, and quoting.