Is command substitution $(foo) bashism?

Question

There are two different syntaxes for command substitution,

FOO=$(echo bar)

and

FOO=`echo bar`

As far as I

Answer 1

Actually, the $(...) command substitution syntax is defined by POSIX, though it's not part of the earlier SVID sh standard. So as long as you don't care about running on pre-POSIX systems, it should be fine.