What is the purpose of `/etc/group-`

On a standard Linux distribution (e.g. Ubuntu) there is usually /etc/group and /etc/group-, where the second one is only readable by root. man group only describes /etc/group. Thus my question: What is the purpose of /etc/group-? Answer It is a backup of the previous copy of the file that is version of the file before … Read more

Error message id: cannot find name for group ID after logging in

BACKGROUND Trevor logs into his account on ssh://foobar.university.edu as one of the developers on the box, and he gets the message: id: cannot find name for group ID 131 Trevor then checks this out using vim /etc/group PROBLEM Trevor discovers that there is no 131 anywhere in the /etc/group file. Trevor then runs id … … Read more

/etc/udev/rules.d/ vs /lib/udev/rules.d/ – which to use and why?

The Arch wiki recommended creating a file in /etc/udev/rules.d/ to fix my Steam controller issues. This worked! However, I noticed that there are no other rules in this folder except for the one I just created. Additionally, all other sources I’ve seen say to place udev rules in /lib/udev/rules.d/, and there are plenty of other … Read more

How to check if a shared library is installed?

My question originates from my problem in getting ffmpeg started. I have installed ffmpeg and it is displayed as installed: whereis ffmpeg ffmpeg: /usr/bin/ffmpeg /usr/bin/X11/ffmpeg /usr/share/ffmpeg /usr/share/man/man1/ffmpeg.1.gz Later, I figured out, that some programs depend on libraries that do not come with the installation itself, so I checked with ldd command what is missing: # … Read more

Global bash_profile

I realize there are /etc/profile and /etc/bashrc files for setting global environment variables and maybe I’m just misunderstanding their purposes, but… Is there a global bash_profile file? I’m using Mac OS X Answer It’s not called bash_profile, but the standard place for global bash configuration is /etc/bash.bashrc. It’s usual to call this from /etc/profile if … Read more

Who creates /etc/{group,gshadow,passwd,shadow}-?

In any linux system I have access to (a couple of Archlinuxes, an Ubuntu, a Debian Sid and a Gentoo) there are the following 4 files in /etc/, all ending with a dash: /etc/group- /etc/gshadow- /etc/passwd- /etc/shadow- On the internet they say that these are just backup files, updated to the next to last change. … Read more

/etc/hosts file refer to another configuration file

How can I get the /etc/hosts file to refer to another configuration file for it’s list of hosts? Example /etc/hosts: ## My Hosts localhost broadcasthost #Other Configurations <Link to /myPath/to/MyConfig/ConfigFile.txt> #Other Addresses MyAwesomeDomain.com SomeplaceIWantToGoTo.com ConfigFile.txt ##My additional Hosts SomeLocation.com AnotherLocation.com How do I add a link/Reference to /etc/hosts file … Read more