Hello, with "GNU bash, version 4.4.12(1)-release (x86_64-pc-linux-gnu)" I get the following behaviour:
+ bash -c 'set -o nounset; echo $x' bash: x: unbound variable + bash -c 'set -o nounset; echo ${x}' bash: x: unbound variable + bash -c 'set -o nounset; echo ${x@Q}' + bash -c 'set -o nounset; echo ${x/a/b}' bash: x: unbound variable "GNU bash, version 5.0.0(1)-release (x86_64-pc-linux-gnu)" behaves identically. So, @Q breaks the 'set -o nounset'. Is this intended? I like using @Q for output of variables with unknown content - is there a better way to do this? Best regards, Martin