[Techtalk] BASH command subsitution

[Conor Daly]

On Sun, Sep 07, 2003 at 06:14:48PM +1000 or so it is rumoured hereabouts, 
Jacinta Richardson thought:
> 
> (In bash apostrophes are just quoting characters.  Backticks say, evaluate
> this first and then I'll work with the result.)

And for those of us (like me) who can never remember how the different
qoutes work:

No quotes:	any variables or evaluated.

$ echo $HOME
/home/cdaly


Single quotes:	variables are not evaluated.

$ echo '$HOME'
$HOME


Double quotes:	variables are evaluated.

$ echo "$HOME"
/home/cdaly


Backticks:	variables are evaluated and their expanded result is run
		as a command.
$ echo `$HOME`
bash: /home/cdaly: is a directory

There's more to it than just that but I can't remember what.  I seem to
recall a website called something like "Advanced bash programming" that
talks about such stuff.  Might be worth a google...

Conor
-- 
Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)
---------------------
Faenor.cod.ie
 12:48pm  up 20 days, 19:21,  0 users,  load average: 0.00, 0.00, 0.00
Hobbiton.cod.ie
 12:46pm  up 20 days, 19:20,  1 user,  load average: 0.08, 0.04, 0.01