3

I have two simple script that enables/disables Cisco AnyConnect when I don't want it trying to connect on each login/network transition. All was fine and dandy, but I wanted to add a line to the hosts file as well. The reason I'm using "echo $password | sudo -S" for most of the commands is because this script is being run from the script menu in Mac OS X. The terminal window does not open to address sudo password prompts. 

#!/bin/bash
#Start_AnyConnect.command

password=`/usr/bin/osascript <<EOT
with timeout of (30 * 60) seconds
    tell application "Finder"
        activate
        set myReply to text returned of (display dialog "Enter your password to authorize AnyConnect startup script" default answer "" with hidden answer)
    end tell
end timeout
EOT`

echo $password | sudo -S echo -e "127.0.0.1\twpad.company.com" >> /etc/hosts
sleep 2

echo $password | sudo -S mv "/Library/LaunchAgents_Disabled/com.cisco.anyconnect.gui.plist" "/Library/LaunchAgents/com.cisco.anyconnect.gui.plist"
echo $password | sudo -S mv "/Library/LaunchDaemons_Disabled/com.cisco.anyconnect.vpnagentd.plist" "/Library/LaunchDaemons/com.cisco.anyconnect.vpnagentd.plist"
echo $password | sudo -S launchctl load /Library/LaunchDaemons/com.cisco.anyconnect.vpnagentd.plist

sleep 5

open /Applications/Cisco/Cisco\ AnyConnect\ Secure\ Mobility\ Client.app

exit 0

The problem I'm having is that

echo $password | sudo -S echo -e "127.0.0.1\twpad.company.com" >> /etc/hosts

appends "-e 127.0.0.1\twpad.company.com" in stead of "127.0.0.1 wpad.company.com" to the hosts file.

If I run the following command by itself it works as expected:

sudo echo -e "127.0.0.1\twpad.company.com" >> /etc/hosts

Is there another way to do this?

Thank you!

jaypal singh
  • 74,723
  • 23
  • 102
  • 147
Sonic84
  • 931
  • 1
  • 10
  • 16
  • 1
    You don't have to use a tab as the white space in Unix host files. Replace it with a space and you shouldn't need the -e switch to echo. – tMC Jan 19 '12 at 02:45
  • 3
    [This](http://stackoverflow.com/questions/84882/sudo-echo-something-etc-privilegedfile-doesnt-work-is-there-an-alterna) might help! – jaypal singh Jan 19 '12 at 02:46

3 Answers3

7

This worked for me on OSX (last tested on Yosemite.) Hope it helps someone else!

sudo sh -c 'echo "127.0.0.1\twpad.company.com\n" >> /etc/hosts'

From the Macworld forums:

The actual explanation is that sudo invokes a subshell as root, and passes only it's first arg to that subshell to run.

Once the command finishes the subshell exits, and it's standard out is piped into >>. This attempts to open up and append to it's file argument as the original UID, which fails due to lack of privilege.

So, the solution is to pass the entire command line, including any redirects, so the whole thing is passed to sudo as one arg.

Community
  • 1
  • 1
restlessdesign
  • 1,489
  • 1
  • 14
  • 18
  • this is good however this will not work if there is any variable inside the string. – kta May 16 '20 at 09:39
  • Was looking for a solution for me that would do just that from the `docker exec` command line. Worked perfectly! Thanks. `docker exec -it container_name sh -c 'echo "IP alias" >> /etc/hosts'` – Pereira May 10 '23 at 19:58
5

The version of echo that is being run doesn't support -e. When you use sudo you get /bin/echo rather than the shell's builtin echo. Use printf instead:

echo $password | sudo -S printf "127.0.0.1\twpad.company.com\n" >> /etc/hosts

Also, see the question linked to in Jaypal's comment regarding redirection and sudo.

Dennis Williamson
  • 346,391
  • 90
  • 374
  • 439
  • 1
    to the question implied by the title "Modify Hosts file with echo" this one is the better answer :) +1 – Shanimal Sep 12 '13 at 19:25
1

Edit or create the file '/etc/hosts.ac' to add your desired host entries. When you start AnyConnect, that file will replace '/etc/hosts'.

No scripted appending will be needed.

George Cummins
  • 28,485
  • 8
  • 71
  • 90