How to escape password for smb mount
Slightly offtopic, but maybe useful if you want to stick to putting credentials with special chars in a Shell variable.
Regarding your bash commands I will point you to several topics:


PWD is a always present ENV variable showing the current working
directory (Print Working Directory). Omit using that name for a PassWorD variable :-).
There is a significant difference in using double quotes and single
quotes. Double quotes embrace a string, which also can contain expandable variable names and is always subject to escape problems. Single quotes define a fix string and will be treated as such, e.g. no variable expansion will be done.


Example:

# fix string
tatooine-2257:~ mallert$ export P='&lt;word'
tatooine-2257:~ mallert$ echo $P
&lt;word
# no variable expansion
tatooine-2257:~ mallert$ export P='&lt;word $PWD'
tatooine-2257:~ mallert$ echo $P
&lt;word $PWD
tatooine-2257:tmp mallert$ echo $PWD
/tmp



Finally - treat variable names in expansion distinguishable from usual text like referring to ${variablename}. (Bourne Shell style)
Try open 'smb://username:password@server/share' - it creates the volume mount for you. If you omit the password, Finder will ask you for it.