Bash argument grouping

args.sh

#!/bin/bash

A=("$@")
X="$@"

echo; echo '"$@":  <-- correct'
for arg in "$@"; do echo "$arg"; done

echo; echo '"${A[@]}":  <-- correct'
for arg in "${A[@]}"; do echo "$arg"; done

echo; echo '"$X":   <-- nope'
for arg in "$X"; do echo "$arg"; done

output.txt

$ ./test.sh one "two three"

"$@":  <-- correct
one
two three

"${A[@]}":  <-- correct
one
two three

"$X":   <-- nope
one two three