Master Linux Login Command: Syntax, Options, and Real-World Examples
This guide explains the Linux login command, covering its purpose, syntax, available options such as -h, -p, -f, parameter usage, and provides practical examples illustrating how to log in, switch users, and handle authentication on systems like Slackware and CentOS.
login: User login system
Function description
The login command presents a login prompt, allowing re‑login, user switching, or changing the logged‑in identity at any time. In Slackware, you can append a username after the command to be prompted for a password. If the /etc/nologin file exists, only the root account may log in; all other users are denied.
Syntax
login [options] [arguments]Option meanings
-h: Use another server to transmit the remote host name for login, allowing it to be recorded in utmp and wtmp.
-p: Preserve environment variables during login.
-f: Skip the second authentication step.
Parameter meaning
Username: specifies the user name to log in as.
Reference examples
Example 1
When the system boots, it invokes this command to ask for the user's password, e.g.:
CentOS Linux 7 (Core)
Kernel 3.10.0-1127.el7.x86_64 on an x86_64
linuxer login: root
Password:Example 2
Logging in with a new identity:
[root@linuxer ~]# login
CentOS Linux 7 (Core)
Kernel 3.10.0-1127.el7.x86_64 on an x86_64
linuxer login:Signed-in readers can open the original source through BestHub's protected redirect.
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