Match newline character

[pk]

Is the =~ operator supposed to recognize \n in patterns? Example:

$ a='abc
def'

$ if [[ $a =~ c\nd ]]; then echo ok; fi

The above produces no output (I've tried using \\n, \\\n too), while using a 
literal newline works:

$ if [[ $a =~ c$'\n'd ]]; then echo ok; fi
ok

Is that expected behavior or am I doing something wrong? I thought \n was 
pretty standard in regular expressions.

Thanks.