Users & Permissions

/etc/password

is a file on Unix-like systems that stores user account information, including usernames, hashed passwords, user IDs, and group IDs.

/etc/shadow

File that stores user account information, including hashed passwords, in a secure manner, ensuring that only authorized processes can access the password data.

/etc/group

is a file on Unix-like systems that defines user groups, including group names, group IDs, and the users who belong to each group.

/etc/gshadow

is a file that stores group information, including hashed passwords for the groups, ensuring enhanced security for group management.

useradd

is a command used in Unix-like systems to create a new user account and set initial configurations.

useradd -c

option that allows you to add a comment or description for the new user being created.

useradd -d

option that specifies the home directory for the new user being created.

passwd

is a command used to change a user's password in Unix-like systems, allowing the user to securely manage their credentials.

usermod

command used to modify an existing user account's properties in a Unix/Linux system.

userdel

is a command used to delete an existing user account from a Unix-like system, removing the user's files and permissions.

groupadd

is a command used to create a new group in a Unix-like system, allowing for the management of user permissions and access rights.

groupmod

command used to modify an existing group account's properties in a Unix/Linux system.

usermod

is a command used to modify an existing user's account details, such as username, home directory, and group memberships in a Unix/Linux system.

groups

Displays the primary and secondary group membership for the specified user account.

Read - r

Permission that allows a user to view the contents of a file or directory in a Unix/Linux system. - Vale: 4

Write - w

Permission that allows a user to modify or delete the contents of a file or directory in a Unix/Linux system. - Value: 2

Execute - x

Permission that allows a user to run a file as a program in a Unix/Linux system. - Value: 1

-rwxrw-r—

File permission notation indicating read, write, and execute permissions for the owner, read and write for the group, and read-only for others in a Unix/Linux system. Value: 764

ls -la

Command to list all files and directories in detail, showing permissions, ownership, and size in Unix/Linux.

chmod

Command used to change file permissions in Unix/Linux systems.

ACL

Access Control List, a list that defines permissions for different users or groups for specific resources in a Unix/Linux system.

chown

Command used to change the ownership of files and directories in Unix/Linux systems.

chgrp

Command used to change the group ownership of a file or directory in Unix/Linux systems.