Linux username rules. We have no idea what those are.
Linux username rules. User Naming Convention in Linux A username is a string of characters identifying a user on a Linux system. Jan 4, 2007 · Explains how to rename the name of the user from OLD_LOGIN to NEW_LOGIN on a Linux-based systems including user's home directory. The authorization ID returned from a successful CONNECT or ATTACH is truncated to the authorization name length listed in SQL and XML limits. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. The Jul 25, 2025 · In the Linux operating system, usernames play a crucial role in the overall security and management of the system. I'm finding inconsistent and incomplete information about what constitutes a valid Linux user name. We have no idea what those are. What characters should be avoided? This will depend on what computer systems you're dealing with. Defining Password Policies Apr 11, 2023 · This article provides a tutorial on setting up a firm password policy for Linux systems using Pluggable Authentication Modules (PAM). A well - structured understanding of Linux usernames is essential for system administrators and regular users alike. While historic UNIX systems restricted the length of a user name to 8 or 16 characters, Linux has rested for a long time on a 32 character limit that is still enforced by adduser at least for system accounts. org Use generic names like "user" and "admin". Important: Do not use a sudo account for everyday use. Nov 8, 2024 · Learn how to effectively manage user groups and permissions in Linux to enhance system security and organization. Just starting out and have a question? If it is not in the man pages or the how-to's this is the place! If you are using a Linux server, usernames, passwords, and filenames must comply with standard Unix naming conventions. May 22, 2013 · I'm writing some web UI pages that can be used to create Linux user accounts. Generally, the same rules apply for user as for group names. Registration is quick, simple and absolutely free. The POSIX standard says that usernames must be from the "portable filename characterset" but the first character must not be a hyphen. Understanding the fundamental concepts, usage methods I'd like to know what the maximum username length is for current GNU/Linux systems, e. Nov 14, 2015 · It is said that in UNIX and other alike systems, we can use hyphen for username in addition to Latin characters, numerics and underscore. On POSIX the set of valid user names is defined as lower and upper case ASCII letters, digits, period, underscore, and hyphen, with the restriction that hyphen is not allowed as first character of the user name. g. On the other hand, the hyphen character is used as operator Are all numeric usernames allowed in RHEL? RHEL 8 is not allowing me to create an all-numeric user. You should check your operating system documentation to see if this is the case. Jul 25, 2025 · This blog post will delve into the fundamental concepts of Linux usernames, their usage methods, common practices, and best practices to help you make the most of user account management in Linux. Ubuntu 11. Jul 25, 2025 · In the Linux operating system, usernames play a crucial role in managing user accounts and controlling access to system resources. Is it unsafe to use my real name as my Linux username? I'm doing a fresh install of Pop!_OS right now and it's asking for my name. Jan 15, 2014 · Having dots in the user name creates some issues with scipts using chown, which still accepts dots as separator between user name and group name. Mar 20, 2019 · Note that useradd may be more restrictive than what is actually valid as a username. Join our community today! Note that registered members When installing Ubuntu, we're restricted to lower-case usernames. 04. Can I create an all numeric username in Red Hat Enterprise Linux 7?. Determining Local Usernames JumpCloud The JumpCloud account username is specified in the Your questions specifically: What is the best username length limit to use to maintain compatibility across all uses? There's no such thing. 1. Edit: It appears from the other responses that some distro's have subverted this Apr 11, 2005 · Linux - Newbie This Linux forum is for members that are new to Linux. shadow has advanced to a 255 character limit. Username Restrictions A name of However, when the authorization ID is interpreted as an operating system user ID or group name, DB2 imposed naming restrictions apply. Your naming convention will assist your organization in naming future users and ensuring consistent usernames. If chown still accepts dots, there will be scripts using this notation, which will break if a user name contains a dot. 8 characters appears to be some historical standard, but I've already noticed on my current U Jan 27, 2011 · So why has the underscore been considered a bad character for user names in Debian (and possibly other distributions) while it has been removed from adduser's NAME_REGEX in Ubuntu? udev (user space /dev) is a user space system that enables the operating system administrator to register user space handlers for events. But recently I registered for a shell based on Ubuntu and logging in is done by the username registered to sign in to that site. com is not really part of the user name per se but an indication were to look this user up. A Linux username is a unique identifier assigned to each user or process on the system. The rules as to what a valid username is may also change via PAM and nsswitch configuration settings. , in Linux. 2. Aug 1, 2007 · Welcome to LinuxQuestions. You are currently viewing LQ as a guest. Yet, there are some restrictions on forming and validating a username. This web UI will be used on CentOS 6 (which is derived from RHEL 6). For example, the Linux and UNIX operating systems can contain up to 8 characters and the Windows operating systems can contain up to 30 characters for user IDs and group names. It covers the configuration files and modules used for password management, as well as password quality, history, aging, and lockout. org, a friendly and active Linux Community. There's only "your" uses, which may include your future uses. Actually, that regular expression permits '-' in user names! The first letter needs to be a-z, but subsequent letters of the user names can be '-', a-z, or 0-9. adduser Rules The adduser command checks if a username is valid by using a regular expression. As such, udev main purpose is to act upon peripheral detection and hot-plugging, including actions that return Home Products Red Hat Enterprise Linux 7 Linux Domain Identity, Authentication, and Policy Guide Chapter 28. This blog post will delve into the fundamental concepts of Linux usernames, their usage methods, common practices, and best practices to help you Need to know the user name/group name character restriction and maximum character length allowed. Windows, for example, has no problems with a period in the Oct 20, 2017 · @MMPP: The thing is that these are not plain Linux user names but virtual ones coming from a database and the @domain. It serves as a way to distinguish between different entities, allowing for proper access control, resource allocation, and auditing. User name length User names tend to become longer and longer over time. The events received by udev 's daemon are mainly generated by the Linux kernel in response to physical events relating to peripheral devices. See full list on paulgorman. Mar 1, 2016 · This tutorial describes how to set password policies such as password length, password complexity, password expiration period etc. A rule to allow names that start with a number and contain some alpha was probably considered not worth the effort; instead there is just a requirement to start with an alpha character. Jun 2, 2016 · Some commands (eg chown) can accept either a username or a numeric user ID, so allowing all-numeric usernames would break that. The portable filename character set are the characters A-Z a-z 0-9 Bringing together multiple existing, disparate services like Windows, Linux, Google Workspace and others into a single directory requires you to consider a naming convention for usernames. Should I use something random and non-identifying? Mar 18, 2024 · 2. User, user ID and group naming rules Note: Some operating systems allow case sensitive user IDs and passwords. vx86y7cv8zh5krbkyf9637kr07ir8bc5ydtcgtkaowhaonw9e