Dealing with spaces in shell scripts

Question

I have read everything I can about quotes (single and double), backslash and more and I'm stuck.
I need to compare files to do some make like things. Many of the files have spaces in the name. Here's the script:
#!/bin/sh
ROOT=$HOME
PROJECT="/Documents/MMM/Victoria/Documentation"
FILE="/Audio Control 1.0 a1.pages"
FULLPATH="${ROOT}${PROJECT}${FILE}"
echo ls -l \"$FULLPATH\"
ls -l \"$FULLPATH\"
and here's the output:
ls -l "/Users/wesM/Documents/MMM/Victoria/Documentation/Audio Control 1.0 a1.pages"
ls: "/Users/wesM/Documents/MMM/Victoria/Documentation/Audio: No such file or directory
ls: 1.0: No such file or directory
ls: Control: No such file or directory
ls: a1.pages": No such file or directory
what's echoed looks exactly right, and if I copy and paste to a shell, it works fine, but when run from within the script, its acting like the double quotes are not there?

Answer 1

If what I'm seeing in the post
ls -l "$FULLPATH"
is correct, then you have told the shell "These are not the quotes you are looking for". So the shell did NOT treat the double quotes as having an special meaning, removed the backslashes, parsed the string into 4 arguments, and passed the 4 arguments including the leading and trailing quotes to the ls command:
arg[1]: "/Users/wesM/Documents/MMM/Victoria/Documentation/Audio
arg[2]: Control
arg[3]: 1.0
arg[4]: a1.pages"
Notice that the leading double quote is part of arg[1], and the trailing double quota is part of arg[4].
You most likely wanted to say something like:
echo ls -l ""$FULLPATH""
ls -l "$FULLPATH"
Notice that I added an extra layer of double quotes to the echo command. The first layer of double quotes tells the shell that this is a single argument. The backslash double quotes tells the shell that these quotes inside of a double quoted string are NOT terminating the string, but rather are to be treated as part of the string.
And no backslashes on the ls command tells the shell that whatever $FULLPATH expands to is to be treated as a single argument.
Always remember it is the shell that parses the command line into tokens so it is also the shell that handles the quoting. The command is just handed an array of strings already broken into individual arguments. The command does not see the quotes. The command does not see the variables.