In this article, you will learn how to change referenced file or directory permissions using the chmod command in Linux (with practical examples).

The chown command is used to modify the user and group ownership of files and directories. It will be helpful to restrict the access permissions for files and directories to selective users and members of group.

The passwd command is used to modify the user’s password and its properties, like deleting the password, expiring the password, deactivating the account, and many more.

When you create a new user account and set a password for that account, the "password expires" status is set to never; however, you can later force them to change their password on their next login.

The chage command is identical to the passwd command used to change user account and password expiration information.

Linux administrators are allowed to create "normal user accounts" with a range from 1000 to 60000 uids, where uid 0 is reserved for "root users" and "system users" are allowed uids from 1 to 999.

The groups command is used to list all the groups to which the specified user belongs. This will make it easier for you to manage users and groups in your system.

The ID command is used to display the user UID, group GID, and groups to which the current user belongs to help you with user management.

The getent command is used to fetch entries from the administrative text files like passwd, group, hosts, services, etc., also known as databases.

The gpasswd command is used to administer “/etc/group” and “/etc/gshadow” file by allowing you to manage group members in your Linux system.

The usermod command is a user management tool to modify user account information like username, user ID, default shell, home directory, and many more.

The which command locates the executable command or file location in the user’s environmental path. It will give you the complete path an executable command or file is pointing towards in your file system.

The whatis command is used to fetch a one-line description of the specified command or tool from the manual pages in your Linux system.

The whereis command is used to find the paths of binary, source, and manual files for a specified command, similarly to the find command but consuming less memory.

The locate command is used to quickly search for files or directories within the indexes in the database file known as updatedb.

The find command is an advanced tool for searching files or directories rigorously in your file system, taking a little longer time than its alternative tools like the locate command.

On Linux, you have multiple tools like which, whereis, locate, and find that can help you find the absolute path for files and directories in your system.

The environment variables are a set of key-value pairs that define the current environment and can affect the behavior of the ongoing programs that are executed in the environment.

The bash uses multiple profiles, also known as shell configuration files, to configure the user’s interactive login or non-login shell.

Whenever you operate a Linux system behind the scenes, you might be encountering the interactive login or non-login shell that you are not aware of.

The printenv command is an alternative to the env command used to fetch the value of a specified variable name (key) used as an argument.