Question

4

Shell tab-completion for service command broken as root

rated 0 times [ 4] [ 0] / answers: 1 / hits: 2886 / 2 Years ago, wed, january 19, 2022, 6:50:36

On most of our servers, tab completion of service names after typing in the service command no longer works, as root. It works just fine as non-root. This is on Ubuntu 12.04. I'm not sure how to approach troubleshooting this.

Demonstrating:

Tab completion works as the normal user zachary, who pressed tab to list completions in the first image:

Tab completion works

But as user root, it doesn't list services as completions (only files):

Now it does not

Any help would be greatly appreciated.

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ippalogu

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2 Years ago

answered 2 Years ago tresein · Accepted Answer

This is disabled by default on Ubuntu.

Read your /root/.bashrc:

# enable programmable completion features (you don't need to enable

# this, if it's already enabled in /etc/bash.bashrc and /etc/profile

# sources /etc/bash.bashrc).

#if [ -f /etc/bash_completion ] && ! shopt -oq posix; then

#    . /etc/bash_completion

#fi

Bash completion is all commented out. Apparently there's a reason for it I'm not aware of (recovery single user mode perhaps?).

The reason for why it does work when you do sudo su, sudo -s, sudo bash is that it doesn't really run login to make you completely root. When running sudo su - or sudo -i it really does completely logs you in as that user. Here, by example of the environment variable $HOME, more of this difference:

gert@gert-laptop:~$ id

uid=1000(gert) gid=1000(gert) groups=1000(gert),4(adm),7(lp),24(cdrom),27(sudo),[...]

gert@gert-laptop:~$ echo $HOME

/home/gert

gert@gert-laptop:~$ sudo -s

root@gert-laptop:~# id

uid=0(root) gid=0(root) groups=0(root)

root@gert-laptop:~# echo $HOME

/home/gert

root@gert-laptop:~# exit

gert@gert-laptop:~$ sudo su -

root@gert-laptop:~# id

uid=0(root) gid=0(root) groups=0(root)

root@gert-laptop:~# echo $HOME

/root