Fix corrupted sudoers file in ubuntu

Instructuin

# If you can access the machine physically , open terminal and run the following command

pkexec visudo

# If you have only ssh access to the machine,
# run the following command, it will freeze your terminal but will fix the issue
# you can get the sudoers file in this gist.

pkttyagent -p $(echo $$) | pkexec cp ~/sudoers /etc/sudoers

sudoers

#
# This file MUST be edited with the 'visudo' command as root.
#
# Please consider adding local content in /etc/sudoers.d/ instead of
# directly modifying this file.
#
# See the man page for details on how to write a sudoers file.
#
Defaults	env_reset
Defaults	mail_badpass
Defaults	secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root	ALL=(ALL:ALL) ALL

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

# Allow members of group sudo to execute any command
%sudo	ALL=(ALL:ALL) ALL

# See sudoers(5) for more information on "#include" directives:

#includedir /etc/sudoers.d