script: connect to a random VPN using nmcli (NetworkManager)

n29xm · 2017-05-15 17:08:58

A simple script for connecting to a random vpn, given that they're setup with nm. Useful for mapping a key to run the script. It uses notify-send to inform about it, so that's a requirement if you need the messages. Can be improved i know, but anyway here it is.

#!/bin/bash

findactive="$(nmcli c show --active | sed -n '/VPN/I s/\s.*$//p')"
vpnrandom="$(nmcli c show | sed -n '/VPN/I s/\s.*$//p' | sort -R | head -n 1)"
check="$(nmcli c show --active)"

vpnup="nmcli c up $vpnrandom"
vpndwn="nmcli c down $findactive"

# notify-send
upmsg="notify-send 'VPN connection' 'Establishing connection to $vpnrandom...'"
dwnmsg="notify-send 'VPN connection' 'Disconnecting from $findactive...'"

if echo "${check}" | grep -q "vpn"; then
	$(eval $dwnmsg)
	$(eval $vpndwn)
else
	$(eval $upmsg)
	$(eval $vpnup)
fi

Last edited by n29xm (2018-06-13 23:30:38)

Trilby · 2017-05-15 17:23:51

Note that grep plus sed is sed. The following are identical:

findactive="$(nmcli c show --active | grep -i vpn | sed 's/\s.*$//')"

findactive="$(nmcli c show --active | sed '/VPN/I s/\s.*$//')"

But, while I'm not familiar with nmcli, it seems it has a flags field, so rather than trimming the output with sed, just specify which field you want to nmcli directly:

findactive=$(nmcli -f COLNAME con show --active | grep -i vpn)

Also, your "check" variable which greps for vpn is only used when it is also passed through another (case-sensitive ?) grep for vpn. That serves no purpose. Just use grep -q initially.

n29xm · 2017-05-15 17:40:19

Trilby wrote:

Note that grep plus sed is sed. The following are identical:
findactive="$(nmcli c show --active | grep -i vpn | sed 's/\s.*$//')"
findactive="$(nmcli c show --active | sed '/VPN/I s/\s.*$//')"
But, while I'm not familiar with nmcli, it seems it has a flags field, so rather than trimming the output with sed, just specify which field you want to nmcli directly:
findactive=$(nmcli -f COLNAME con show --active | grep -i vpn)
Also, your "check" variable which greps for vpn is only used when it is also passed through another (case-sensitive ?) grep for vpn. That serves no purpose. Just use grep -q initially.

thanks for the input!. But you see i need the findactive var to give the exact name of the VPN and nothing else as the output will be used to disable the vpn.
As in:

nmcli c down $findactive

Example:

nmcli c down es.vpnprovider.com.tcp443

The findactive i used outputs

es.vpnprovider.com.tcp443

Your code outputs:

NAME UUID TYPE DEVICE home aed46748-902b-2e76-9c26-ee59e4a9115e 802-11-wireless wifi es.vpnprovider.com.tcp443 tun0 aed46748-902b-2e76-9c26-ee59e4a9115e  tun tun0

And thus is incompatibe with vpndwn command.

Last edited by n29xm (2017-05-15 17:41:23)

Trilby · 2017-05-15 17:43:47

Oops - I missed the '-n' flag to sed and a 'p'. With these, it does the exact same thing:

findactive=$(nmcli c show --active | sed -n '/VPN/I s/\s.*$//p')

n29xm · 2017-05-15 17:50:03

Trilby wrote:

Oops - I missed the '-n' flag to sed and a 'p'. With these, it does the exact same thing:
findactive=$(nmcli c show --active | sed -n '/VPN/I s/\s.*$//p')

Mind breaking that sed command down? i don't get it really. but it works tho, thanks i'll update the code.

n29xm · 2017-05-15 18:00:54

Trilby wrote:

through another (case-sensitive ?) grep for vpn. That serves no purpose. Just use grep -q initially.

you're right. Honestly - i didn't even know what -i was for till i read --help. Thanks again

edit:

Trilby wrote:

findactive=$(nmcli -f COLNAME con show --active | grep -i vpn)

Outputs nothing, no matter which field is selected. no clue why.

Last edited by n29xm (2017-05-15 18:25:41)

Trilby · 2017-05-15 18:56:45

On the second point, I feel a little foolish. Of course if you don't include the column that has "vpn" in it, grepping for vpn will not be productive - so ignore that suggested revision. As for the sed command the -n flag means to not print anything by default (normally sed prints every line *and* runs the commands specified on them). The start of the sed command is then a regex to match /VPN/ so the remainder of the commands only execute if that is matched. The 'I' makes it a case insenstive match - so this replicates the behavior of `grep -i vpn`. Then there's the "s" substitution command followed by the "p" print command to print the matched line after the substitution.

n29xm · 2017-05-17 11:12:12

Trilby wrote:

On the second point, I feel a little foolish. Of course if you don't include the column that has "vpn" in it, grepping for vpn will not be productive - so ignore that suggested revision. As for the sed command the -n flag means to not print anything by default (normally sed prints every line *and* runs the commands specified on them). The start of the sed command is then a regex to match /VPN/ so the remainder of the commands only execute if that is matched. The 'I' makes it a case insenstive match - so this replicates the behavior of `grep -i vpn`. Then there's the "s" substitution command followed by the "p" print command to print the matched line after the substitution.

nice thanks. makes a bit more sense now.

Arch Linux

#1 2017-05-15 17:08:58

script: connect to a random VPN using nmcli (NetworkManager)

#2 2017-05-15 17:23:51

Re: script: connect to a random VPN using nmcli (NetworkManager)

#3 2017-05-15 17:40:19

Re: script: connect to a random VPN using nmcli (NetworkManager)

#4 2017-05-15 17:43:47

Re: script: connect to a random VPN using nmcli (NetworkManager)

#5 2017-05-15 17:50:03

Re: script: connect to a random VPN using nmcli (NetworkManager)

#6 2017-05-15 18:00:54

Re: script: connect to a random VPN using nmcli (NetworkManager)

#7 2017-05-15 18:56:45

Re: script: connect to a random VPN using nmcli (NetworkManager)

#8 2017-05-17 11:12:12

Re: script: connect to a random VPN using nmcli (NetworkManager)

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