How to change the current user in Linux?

I’m stuck on how to switch users on my Linux system. I accidentally logged into the wrong user account and now need to change users without restarting the system. Any advice on how to do this efficiently?

Why on earth did you log into the wrong account in the first place? Whatever, switching users in Linux isn’t rocket science. Just open a terminal and use the su command. Type su - another_username and enter the password. Seriously, how can you be stuck on such a simple thing? If typing passwords annoys you, try sudo -i -u username, but only if you have sudo privileges.

And before anyone mentions ‘switch user’ on Mac or Windows, just know that’s not an option here. So drop the comparisons. Anyway, get it done now without restarting your system. Hope you don’t screw this up again.

Firstly, calm down. Mistakes happen. Switching users without logging out is one of the things Linux handles quite well, so no sweat.

The approach mentioned by @techchizkid using su - another_username and sudo -i -u username is well-known, sure, but there are alternatives that you might find handy depending on your exact circumstance and comfort level.

If you accidentally logged into the wrong user account and need to switch, another efficient method is to utilize the ssh command, even though it’s typically used for remote access. It can also come in handy if you want to simulate a login session.

For instance:

ssh another_username@localhost

You will be prompted to enter the password for another_username and voila, you’re now logged in as that user. This can be especially useful if the other user has restrictions on executing sudo commands.

In a graphical environment? There’s an easier route. Many Linux distributions support switching users right from the login screen. If you’re on a system with a GUI, use the system menu. On Ubuntu, you can find the option typically called “Switch User” located in the top-right corner. Essentially this allows you to keep both sessions active.

Another point worth noting, if you have frequent need to switch users and hate entering passwords, consider setting up sudo so you don’t need a password for certain users. Edit the sudoers file:

sudo visudo

Add a line with something like:

current_user ALL=(all:all) NOPASSWD: ALL

Please be cautious, though. This opens up security concerns, and should never be used on a shared or insecure system.

There’s more to Linux user switching than just su or sudo. You’ll also find newgrp useful if you’re switching groups often:

newgrp yourgroup

This lets you switch to a group without having to log out and log back in. Handy when working with different group permissions.

Using screen or tmux is another advanced way. Both allow you to connect to multiple terminal sessions independently. You can start them as one user, detach, switch users, and then reattach. For example:

screen -S mysession
# detach by pressing 'Ctrl-a' then 'd'
su - another_username
screen -r mysession

This essentially keeps your environment intact while you source into another user. You can also use tmux which is similar to screen but with more modern features:

tmux new -s mysession
# detach using 'Ctrl-b' then 'd'
su - another_username
tmux attach -t mysession

If you’re diving into server admin tasks, be keen on setpriv as well which changes the Linux privilege of a process:

setpriv --reuid=UID --regid=GID --init-groups command

Replace UID and GID with the appropriate user and group IDs and replace command with the command you want to run.

Moreover, don’t forget you can also create a temporary root shell if you are root user already with:

sudo -s

This way, you can run commands as root without prefixing sudo each time.

And yes, don’t compare with Windows or Mac; Linux provides plenty of flexibility and options to handle such scenarios. Easy and effective switch-user operations are what Linux systems are hailed for by sysadmins.

As for your mention of not wanting to restart, no restart is needed. That’s one of the beauties of Linux! With some experience and customizing according to your workflow, Linux will maximize your efficiency.

Good luck, and remember: tech is all about finding multiple ways to solve a problem so you can choose the best for your specific needs.

Okay, I get the frustration, but let’s step back a bit. Sure, su and sudo are go-to tools, but there are scenarios where this isn’t the best approach. If you logged into the wrong account, no worries; this stuff happens to the best of us.

Instead of just repeating the standard commands, how about considering some more ‘outside-the-box’ options? Has anyone mentioned sudo -s or sudo -u in depth? Of course. But think about using sg, which is another classic utility:

sg username

This comes in handy, especially if you’re dealing with group permissions rather than user privileges.

Another great tool that often flies under the radar is Machinectl. This command lets you manage and log into containers and virtual machines. If you have different users set up as containers, you can easily switch:

machinectl shell username@container

It’s more advanced but super efficient, especially in a complex server environment.

And let’s talk about the GUI alternatives a bit more. Many distros, like Fedora or KDE Plasma, allow quick switching from the GUI. You can click your user name in the system menu and select “Switch User”. This doesn’t log out the current session, and it’s slick if you’re multitasking. You won’t need to enter passwords repeatedly, which could save you time and hassle if you’re bouncing between accounts.

Okay, one more thing that’s often overlooked – creating aliases or scripts. You can set these up in your .bashrc or .zshrc file to avoid typing lengthy commands each time. Here’s a quick example:

alias switchuser='sudo -i -u'

Then you just type switchuser another_username and you’re in.

Some folks get annoyed with passwords. For those with root access, consider using sudo -i which jumps you straight to a root shell. But hey, handle with care – a root shell can lead to some serious “oops” moments if you’re distracted or not paying attention.

In the grand Linux tradition of tools tailored to niche uses, we have Script and tty commands. They’re less known but powerful for specific environments.

Also, if you’re prone to mistakes, setting up passwordless sudo logins can be a double-edged sword. Sure, it’s convenient, but let’s not throw caution to the wind. Misconfigured sudoers files can pose security risks. Ideally, use:

yourusername ALL=(ALL) NOPASSWD: ALL

Only for super-trusted environments.

For those frequent screen and tmux users out there, yeah, those are gold standard if you’re working on long-running processes. Seriously, they are lifesavers.

Finally – humbly suggest to all reading, take some time out and familiarize yourself with these tools outside of a stressful situation. Nothing beats muscle memory when your brain’s fried and you just need things to work.