Man Pages in login

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Section 1: Executable programs or shell commands

login.1

Begin session on the system

newgrp.1

Log in to a new group

sg.1

Execute command as different group id

su.1

Change user id or become superuser
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Section 5: File formats and conventions

faillog.5

Login failure logging file

login.defs.5

Shadow password suite configuration
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Section 8: System administration commands

faillog.8

Display faillog records or set login failure limits

lastlog.8

Reports the most recent login of all users or of a given user

nologin.8

Politely refuse a login