Ubuntu Unleashed 2019 Edition: Covering 18.04, 18.10, 19.04

Allowed and forbidden passwords Frequency of mandated password changes Retrieval or replacement of lo ...

matthew@seymour:~$ cat /etc/passwd root:x:0:0:root:/root:/bin/bash bin:x:2:2:bin:/bin:/bin/sh sys:x:3:3:sys:/dev:/bin/sh games: ...

matthew@seymour:~$ sudo cat /etc/shadow root:!:14547:0:99999:7::: daemon:*:14544:0:99999:7::: bin:*:14544:0:99999:7::: sys:*:145 ...

since January 1, 1970, that the account has been disabled. A “reserved” field that is not currently al ...

envfile=/etc/default/locale auth sufficient pam_succeed_if.so user ingroup nopasswd ...

Changing Passwords in a Batch On a large system, there might be times when a large number of users ...

Discussing that is beyond the scope of this chapter, but for the sake of argument, for the scenario and d ...

The syntax for the su command is as follows: Click here to view code image matthew@seymour:~$ su option usern ...

root~# To return to the regular user’s identity, just type the following: root~# exit This takes you to the r ...

forget to exit root, you could cause severe damage to the system. It is usually better to choose one method o ...

# Host alias specification # User alias specification # Cmnd alias specification # User privilege sp ...

john 192.168.1.87=/usr/bin/users-admin If you want to give the editor group system-wide permission with no pas ...

On large systems with many users, you often need to control the amount of disk space a user can use. ...

Click here to view code image matthew@seymour:~$ sudo mount -o ro,remount partition_to_be_remounted mount_poi ...

NOTE Ubuntu does not support any graphical tools that enable you to configure disk quotas. A Quota mini-HOWT ...

even discusses why you might not want to use them [http://tldp.org/HOWTO/Security-HOWTO/—A must-read HOWTO](http ...

CHAPTER 14 Automating Tasks and Shell Scripting IN THIS CHAPTER Scheduling Tasks Basic Shell Control Writing a ...

Using at and batch to Schedule Tasks for Later If you want to run a time-intensive task, but you do not wan ...

You can specify an exact date and time by using HH:MM MM/DD/YY format (for example, 16:40 22/12/18 ...

Click here to view code image matthew@seymour:~$ atq 14 2012-01-20 23:33 a matthew 16 ...