I cannot download from Ubuntu Software and failed to fix child error

Question

I have currently Ubuntu 16.04. I cannot access the terminal to place commands. The terminal is taken up this error message: [There was an error creating the child process for this terminal] even when I close it. Below is result from attempting to install tinc VPN.

graeme@graeme-ThinkCentre:~$  sudo snap connect tinc-vpn:network-manager
graeme@graeme-ThinkCentre:~$  sudo snap connect tinc-vpn:network-observe
graeme@graeme-ThinkCentre:~$   sudo snap connect tinc-vpn:network-setup-control
graeme@graeme-ThinkCentre:~$ /var/snap/tinc-vpn/
-bash: /var/snap/tinc-vpn/: Is a directory
graeme@graeme-ThinkCentre:~$  sudo mkdir /var/snap/tinc-vpn/tinc
graeme@graeme-ThinkCentre:~$   sudo chown username:username /var/snap/tinc-vpn/tinc -R
chown: invalid user: ‘username:username’
graeme@graeme-ThinkCentre:~$  sudo chmod 775 /var/snap/tinc-vpn/tinc -R
graeme@graeme-ThinkCentre:~$ sudo --pidfile=/run/shm/snap.tinc-vpn.tinc.pid
sudo: unrecognized option '--pidfile=/run/shm/snap.tinc-vpn.tinc.pid'
usage: sudo -h | -K | -k | -V
usage: sudo -v [-AknS] [-g group] [-h host] [-p prompt] [-u user]
usage: sudo -l [-AknS] [-g group] [-h host] [-p prompt] [-U user] [-u user]
            [command]
usage: sudo [-AbEHknPS] [-r role] [-t type] [-C num] [-g group] [-h host] [-p
            prompt] [-u user] [VAR=value] [-i|-s] [<command>]
usage: sudo -e [-AknS] [-r role] [-t type] [-C num] [-g group] [-h host] [-p
            prompt] [-u user] file ...
graeme@graeme-ThinkCentre:~$ sudo -c /var/snap/tinc-vpn/tinc/(netname)
-bash: syntax error near unexpected token `('

Answer 1

The most likely reason that you can't install tinc VPN from the software center is that you don't have the Universe Repository enabled After enabling it you should be able to install tinc normally as it's freely available for your version of Ubuntu in the Universe repository. A quick glance at your commands and output indicates that you've misunderstood the instructions. For example sudo chown username:username /var/snap/tinc-vpn/tinc -R in this context username means your username so in your case the command would be sudo chown graeme:graeme /var/snap/tinc-vpn/tinc -R based upon your output and prompt. As far as the error creating child process for the terminal you may find this answer useful. You may also wish to go over the instructions again as shown below: