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On Ubuntu 16.04, I do not like the WiFi to be enable automatically on OS startups. Inspired by How can I keep a wireless card's radio powered off by default? , I write a silenceWiFi.service as

[Unit]
Description=Disable Wi-Fi on startup
Before=NetworkManager.service
[Service]
Type=oneshot
ExecStart=/etc/default/silenceWiFi
[Install]
WantedBy=multi-user.target

with /etc/default/silenceWiFi only the following simple lines

#!/bin/sh
/bin/sed -i -re "s/^(WirelessEnabled=).*\$/\1false/" /var/lib/NetworkManager/NetworkManager.state

It works as expected.

However, If I change the line ExecStart in silenceWiFi.service to be

ExecStart=/bin/sed -i -re '\"s/^(WirelessEnabled=).*\\$/\\1false/\"' /var/lib/NetworkManager/NetworkManager.state

there are always errors with the service

 sudo systemctl status silenceWiFi.service

will produce the following messages

 ● silenceWiFi.service - Disable Wi-Fi on startup
     Loaded: loaded (/lib/systemd/system/silenceWiFi.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Fri 2016-08-26 16:10:46 CST; 10s ago
     Process: 20423 ExecStart=/bin/sed -i -re "s/^(WirelessEnabled=).*\$/\1false/" /var/lib/NetworkManager/NetworkManager.state (code=exited, Main PID: 20423 (code=exited, status=1/FAILURE)
  Aug 26 16:10:46 Y12 systemd[1]: Starting Disable Wi-Fi on startup...
  Aug 26 16:10:46 Y12 sed[20423]: /bin/sed: -e expression #1, char 1: unknown command: `"'
  Aug 26 16:10:46 Y12 systemd[1]: silenceWiFi.service: Main process exited, code=exited, status=1/FAILURE
  Aug 26 16:10:46 Y12 systemd[1]: Failed to start Disable Wi-Fi on startup.
  Aug 26 16:10:46 Y12 systemd[1]: silenceWiFi.service: Unit entered failed state.
  Aug 26 16:10:46 Y12  systemd[1]: silenceWiFi.service: Failed with result 'exit-code'.

Is it possible to put the sed in ExecStart line, which works without the need for a shell script (say, without the help of /etc/default/silenceWiFi).

Chen Deng-Ta
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1 Answers1

0

Yeah, just using the following line

ExecStart=/bin/sed s/^WirelessEnabled=true/WirelessEnabled=false/ -i /var/lib/NetworkManager/NetworkManager.state

using the cmd line in "Modern" solutione instead, the systemd do not complain any more.

sudo systemctl status silenceWiFi.service

you will see

● silenceWiFi.service - Disable Wi-Fi on startup
  Loaded: loaded (/lib/systemd/system/silenceWiFi.service; enabled; vendor preset: enabled)
  Active: inactive (dead) since Fri 2016-08-26 17:29:12 CST; 4min 31s ago
  Process: 2506 ExecStart=/bin/sed s/^WirelessEnabled=true/WirelessEnabled=false/ -i /var/lib/NetworkManager/NetworkManager.state (code=ex
  Main PID: 2506 (code=exited, status=0/SUCCESS)

Aug 26 17:29:12 Y12 systemd[1]: Starting Disable Wi-Fi on startup...
Aug 26 17:29:12 Y12 systemd[1]: Started Disable Wi-Fi on startup.
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Chen Deng-Ta
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