readonly a=A
readonly b=B
Ok:0
+
hush: a=A: readonly variable
Fail:1
hush: a=A: readonly variable
Fail:1
+
hush: a=Z: readonly variable
Fail:1
+
hush: a=Z: readonly variable
b=B
^^^a is not exported
+hush: a=Z: readonly variable
+Visible:42
+
hush: a: readonly variable
Fail:1
unset a b
-
+#
readonly a=A
b=B
readonly b
echo Ok:$?
env | grep -e^a= -e^b= # shows nothing
+echo
# these should all fail (despite the same value being assigned)
# bash does not abort even in non-interactive more (in script)
true; a=A
true; readonly a=A
echo Fail:$?
+echo
# in bash, assignment in export fails, but export succeeds! :)
# we don't mimic that!
true; export a=Z
-echo Fail:$?; true
+echo Fail:$?
#env | grep '^a='
#echo "^^^a is exported"
export -n a # undo that bashism, if it happens
+echo
export b
# this fails to both set and export a:
-a=Z env | grep '^[ab]=' # command still runs
+a=Z env | grep '^[ab]='
echo "^^^a is not exported"
+# but external command does get executed, and $? is not mangled (stays 42):
+(exit 42); a=Z env echo Visible:$?
-unset a
-echo Fail:$?; true
+echo
+true; unset a
+echo Fail:$?