1f() { for i; do echo "|$i|"; done; }
2
3echo Unquoted 1:
4x='1 2'; f a${x:+ 'x y' $x ''  "$x" `echo A B` "`echo C D`" z}b
5echo Quoted 1:
6x='1 2'; f "a${x:+ 'x y' $x ''  "$x" `echo A B` "`echo C D`" z}b"
7
8echo Unquoted 2:
9x='1 2'; f a${x:+'x y' $x ''  "$x" `echo A B` "`echo C D`" z }b
10echo Quoted 2:
11x='1 2'; f "a${x:+ 'x y' $x ''  "$x" `echo A B` "`echo C D`" z }b"
12
13#echo Unquoted 3:
14#e=
15#x='1 2'; f a${x:+'x y' $x ''  "$x" $e $e "$e" $e `echo A B` "`echo C D`" z }b
16#echo Quoted 3:
17#x='1 2'; f "a${x:+ 'x y' $x ''  "$x" $e $e "$e" $e `echo A B` "`echo C D`" z }b"
18