Linux 6: User Management II

Add Users

useradd [user] [options]

OPTIONS

-b, --base-dir
-d, --home HOME_DIR
-e, --expiredate
-f, --inactive (The number of days after a password expires until the account is permanently disabled)
-u, --uid (user id)
-g, --gid (group id)
-G, --groups A list of supplementary groups
-p, --password (The encrypted password)

Delete User

userdel [user] [options]

OPTIONS

-f, --force
-r, --remove (Files in the user's home directory will be removed)

Modify User Account

usermod [options] [user]

OPTIONS

-a, --append
-d, --home HOME_DIR
-e, --expiredate
-f, --inactive INACTIVE (The number of days after a password expires until the account is permanently disabled)
-g, --gid
-G, --groups
-l, --login NEW_LOGIN (The name of the user will be changed)
-L, --lock (Lock a user's password)
-m, --move-home
-p, --password

Setting user permission

Sequence:

Read Write Execute

Binary

Read — 4
Write — 2
Execute — 1

sudo chmod -Rv 755 /path/to/folder/

It can be read as permissions to Owner 7, to Group 5, to Others 5
-OR-
It can be display as

rwxr-xr-x

It's equivalent to 755