use sed to substitute ${domain}. Is there a better way?

getssl

@@ -1287,6 +1287,7 @@ usage() { # echos out the program usage
 write_domain_template() { # write out a template file for a domain.
   if [[ -s "$WORKING_DIR/getssl_default.cfg" ]]; then
     cp $WORKING_DIR/getssl_default.cfg "$1"
+    sed -i 's/\$\{domain\}/${domain}/g "$1"
   else
     cat > "$1" <<- _EOF_domain_
     # Uncomment and modify any variables you need