Bash commands

[Freddy Freeloader <fredddy@cableone.net>]

Hi all,

I downloaded the Advanced Bash Scripting Guide the other day an have 
started to work my way through it.  I'm fairly new to bash so I get more 
than a little confused when the output I get is nothing similar to what 
the ABS Guide says it should be. 

Here is what has me confused at the moment.

b=${a/23/BB}

echo "b = $b"

Now the ABS guide says that where I'm setting b it should be 
substituting BB for 23.  It also says that the output of 'echo "b - $b"' 
should be: b = BB35

However, what I get as output is as follows:

ffreeloader@Job:~$ echo "b = $b"
b = total 520716
drwxr-sr-x  2 ffreeloader ftp        48 2005-10-13 07:50 script
-rw-r--r--  1 ffreeloader ftp 532692172 2005-10-12 09:38 server_2003.zip

Now in my playing around this morning I've been using some command 
substitution from the bash prompt that included cd'ing into a directory 
that has the files in it that are listed above.  I assume that somehow 
setting $b to the value I set it to is calling the history command in 
the bash shell and that's how I'm getting this output.  However, I don't 
know why or how it works.

Is there anyone around who can explain this to me?  I sure would 
appreciate it.