Regex syntax error with Sed command in Ubuntu 9.04 - regex

Question

I have the sed command like this:
radius_clientsfile=clients.conf
iface_netsize="/64"
wireless_prefix=fd04:bd3:80e8:3::
sed -i "/client $wireless_prefix\\$iface_netsize/ {n s/\(\W*secret\W*=\W\).*/\1$key/}" $radius_clientsfile
clients.conf has the content like this:
client fd04:bd3:80e8:3::/64 {
secret = 00000000000000000000000000000001
}
which aim to replace value of secret by key in clients.conf file. For Example, if key is 00000000000000000000000000000002, the content of clients.conf should be changed as following:
client fd04:bd3:80e8:3::/64 {
secret = 00000000000000000000000000000002
}
This script work on OpenWRT attitude adjustment r35400 for armv5tejl
However, it can not work in Ubuntu 9.04 with error:
sed: -e expression #1, char 36: extra characters after command
Could anyone help me for this situation?

Answer 1

I think you need add a ; between command n and command s, like this
sed -i "/client $wireless_prefix\\$iface_netsize/ {n; s/\(\W*secret\W*=\W\).*/\1$key/}" $radius_clientsfile
This working in my cygwin environment.

Answer 2

You need to separate the commands in the command block with a semi-colon, so add a ; after the n command to separate it from the following command.
Like this:
{n;s/\(\W*secret\W*=\W\).*/\1$key/}