SHELL: line 1: syntax error: bad substitution
SHELL: line 1: syntax error: bad substitution
-_0_ __
+__
_z_ _z_
_ _ _ _ _
_aaaa _ _ _word _word
# now some funky ones.
# ${V+word} "if V unset, then substitute nothing, else substitute word"
# ${V:+word} "if V unset or '', then substitute nothing, else substitute word"
-# bash doesn't accept ${#+}. ash prints 0 (not $#): "len of $+"
-echo _${#+}_ _${#:+}_
+#
+# ${#:+} is a :+ op on $#, but ${#+} (and any other ${#c}) is "length of $c",
+# not + op on $#.
+# bash and dash do not accept ${#+}. it's possible for some shell to skip
+# the check that c is valid and interpret ${#+} as "len of $+". Not testing it.
+# echo _${#+}_
+echo _${#:+}_
# Forms with non-empty word work as expected in both ash and bash.
echo _${#+z}_ _${#:+z}_
hush: syntax error: unterminated ${name}
hush: syntax error: unterminated ${name}
-__ __
+__
_z_ _z_
_ _ _ _ _
_aaaa _ _ _word _word
# now some funky ones.
# ${V+word} "if V unset, then substitute nothing, else substitute word"
# ${V:+word} "if V unset or '', then substitute nothing, else substitute word"
-# bash doesn't accept ${#+}. ash prints 0 (not $#): "len of $+"
-echo _${#+}_ _${#:+}_
+#
+# ${#:+} is a :+ op on $#, but ${#+} (and any other ${#c}) is "length of $c",
+# not + op on $#.
+# bash and dash do not accept ${#+}. it's possible for some shell to skip
+# the check that c is valid and interpret ${#+} as "len of $+". Not testing it.
+# echo _${#+}_
+echo _${#:+}_
# Forms with non-empty word work as expected in both ash and bash.
echo _${#+z}_ _${#:+z}_