sudo command is not working in ubuntu 14.04

问题

In my machine sudo command is not working and it is giving following message.

sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set

When I tried

ls -l /usr/bin/sudo it is giving

-rwxr-xr-x 1 'whoami' root 155008 Aug 28 2015 /usr/bin/sudo

回答1:

It looks like, at some point, someone tried to take over ownership of the sudo executable but used single quotes rather than backticks:

chown 'whoami'  /usr/bin/sudo     # The wrong way
chown `whoami`  /usr/bin/sudo     # The right way
chown $(whoami) /usr/bin/sudo     # Another right way

Note that I say "right way" but it's probably not something anyone should be doing anyway.

You're going to have to figure out some other way of getting into the root account (such as booting in single user mode) and changing the ownership and permissions back to what they should be:

chown root /usr/bin/sudo
chmod u+s /usr/bin/sudo

After that, it should be back at the correct:

-rwsr-xr-x 1 root root 155008 Aug 28  2015 /usr/bin/sudo

来源：https://stackoverflow.com/questions/36566972/sudo-command-is-not-working-in-ubuntu-14-04