busybox/shell/ash_test/ash-vars/var_bash3.tests

a='abc'
r=${a//b/\041#}
echo 1 $r
echo 2 ${a//b/\041#}
echo 3 "${a//b/\041#}"

a='abc'
r=${a//b/\\041#}
echo 4 $r
echo 5 ${a//b/\\041#}
echo 6 "${a//b/\\041#}"

a='abc'
b='\041#'
r=${a//b/$b}
echo 7 $r
echo 8 ${a//b/$b}
echo 9 "${a//b/$b}"

a='abc'
b='\'
r="${a//b/$b}"
echo 10 $r
echo 11 ${a//b/$b}
echo 12 "${a//b/$b}"

a='abc'
b='\\'
r="${a//b/$b}"
echo 13 $r
echo 14 ${a//b/$b}
echo 15 "${a//b/$b}"

a='abc'
b='\t'
r="${a//b/$b}"
echo 16 $r
echo 17 ${a//b/$b}
echo 18 "${a//b/$b}"
echo 19 ${a//b/\t}
echo 20 "${a//b/\t}"