команда sed не может понять с помощью специальных символов

Question 1

Что-то звучит испорчено в вашей конфигурации. Не нужно вводить имя домена, если вы находитесь в одном домене.

Из man dig:

NAME
       dig - DNS lookup utility

DESCRIPTION
       dig (domain information groper) is a flexible tool for interrogating
       DNS name servers. It performs DNS lookups and displays the answers that
       are returned from the name server(s) that were queried. Most DNS
       administrators use dig to troubleshoot DNS problems because of its
       flexibility, ease of use and clarity of output. Other lookup tools tend
       to have less functionality than dig.

       Unless it is told to query a specific name server, dig will try each of
       the servers listed in /etc/resolv.conf. If no usable server addresses
       are found, dig will send the query to the local host.

Я искал dig (d4) Показывает настройки сети и примеры:

terrance@terrance-ubuntu:~$ cat /etc/resolv.conf 
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 10.0.0.1
search local

terrance@terrance-ubuntu:~$ nslookup DD-WRT
Server:     10.0.0.1
Address:    10.0.0.1#53

Name:   DD-WRT.local
Address: 10.0.0.1

terrance@terrance-ubuntu:~$ dig DD-WRT

; <<>> DiG 9.10.3-P4-Ubuntu <<>> DD-WRT
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56329
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;DD-WRT.                IN  A

;; ANSWER SECTION:
DD-WRT.         0   IN  A   10.0.0.1

;; Query time: 0 msec
;; SERVER: 10.0.0.1#53(10.0.0.1)
;; WHEN: Wed Apr 11 18:31:50 MDT 2018
;; MSG SIZE  rcvd: 51


terrance@terrance-ubuntu:~$ dig terrance-ubuntu

; <<>> DiG 9.10.3-P4-Ubuntu <<>> terrance-ubuntu
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4063
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;terrance-ubuntu.       IN  A

;; ANSWER SECTION:
terrance-ubuntu.    0   IN  A   10.0.0.100

;; Query time: 0 msec
;; SERVER: 10.0.0.1#53(10.0.0.1)
;; WHEN: Wed Apr 11 18:32:37 MDT 2018
;; MSG SIZE  rcvd: 60

Мой вывод - это то, что в вашей настройке сети неверно.

Question 2