Linux User Management: Creation, Deletion, and Permission Assignment

Linux user management is fundamental to system maintenance, distinguishing permissions through user (UID) and group (GID) identifiers to ensure security and resource isolation. Core operations include: User creation requires administrative privileges, using `useradd -m username` (-m creates a home directory) followed by `passwd username` to set a password. Viewing user information uses `id`, and switching users is done with `su -`. User deletion is performed via `userdel -r username` (-r removes the home directory). Permission management is achieved through `chmod` (letter/numeric method), `chown`/`chgrp` (change owner/group), with the `-R` flag for recursive directory permission changes. Temporary privilege elevation with `sudo` requires adding the user to the `wheel` (CentOS) or `sudo` (Ubuntu) group using `usermod -aG`. Caution is advised during operations to avoid accidental user deletion or incorrect permission assignments.