Learning Bash: Quoting spaces

From: Sak (sak_at_invalid.address)
Date: 09/30/03 

Date: Mon, 29 Sep 2003 23:20:40 -0700

Everyone,

I'm working through O'Reilly's 'Learning the bash shell' and have run into
some questions. Here's the first one:

The following function is offered in Chapter 4

pushd ()
{
     dirname=$1
     DIR_STACK="$dirname ${DIR_STACK:-$PWD' '}"
     cd ${dirname:?"missing directory name."}
     echo "$DIR_STACK"
}

When I run this, the first directory that gets pushed onto the stack gets a
literal ' ' at the end of it, while the subsequent directories pushed onto
the stack do not. Like this...

/home/sak/wip/composition/ /home/sak/wip/lup/ /home/sak' '

I've managed to figure out that if I remove the strong quotes from around
the space, like this...

DIR_STACK="$dirname ${DIR_STACK:-$PWD }

...I get the desired result. I was just wondering why? In the previous
case, why did the literal quotes only end with the first item pushed onto
the stack, and not the rest? 

-- 
Thanks,
Sak.

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