4. Ubuntu 18.04.3 User/Group Management and Miscellaneous

Hi,

In this section of post for Ubuntu 18.04.3 configuration, I would cover the topic of User/Group Management and other neccesary commands for Ubuntu server operations.
This post would highlight the command usage but would also bring the reference summary of more detailed usage of commands required.

• Listing/Adding/Removing New User

  Reference: https://websiteforstudents.com/how-to-list-all-user-accounts-on-ubuntu-16-04-18-04/

  
  # List User
  sudo less /etc/passwd
  
  sudo awk -F: '{ print $1}' /etc/passwd
  
  sudo getent passwd
  
  

  Reference: https://linuxize.com/post/how-to-list-users-in-linux/

  
  # System and Normal Users
  
  sudo grep -E '^UID_MIN|^UID_MAX' /etc/login.defs
  sudo getent passwd {1000..60000}
  
  

  

  The following post provides a very comprehensive example of user/group management

  https://vitux.com/add-and-manage-user-accounts-in-ubuntu-18-04-lts/

• Test sudo user access
  Once a new user is added to the Ubuntu, and is assigned to sudo user group. One can switch user and test its sudo access as follows:

  
  #  To run as another user for a prolonged period of time then use the su command
  su - username
  
  

  Reference:
  https://linuxize.com/post/how-to-create-a-sudo-user-on-ubuntu/
  https://phoenixnap.com/kb/how-to-create-sudo-user-on-ubuntu

• Process Management
  To manage the running processes on the Ubuntu, the ps/top/htop command can come in handy.

  

  Reference:
  https://www.cyberciti.biz/faq/how-to-check-running-process-in-ubuntu-linux-using-command-line/

  https://www.tecmint.com/command-line-tools-to-monitor-linux-performance/

• Service/Daemon Management

  Just as in windows there are numerous background servies that run, in Ubuntu universe the service (or say daemon) management is driven by systemctl and couple of great article on their management are as follows:

  

  

  Reference:
  https://vitux.com/how-to-start-stop-or-restart-services-in-ubuntu/
  https://www.digitalocean.com/community/tutorials/how-to-use-systemctl-to-manage-systemd-services-and-units#service-management
  https://medium.com/@benmorel/creating-a-linux-service-with-systemd-611b5c8b91d6

• Configuring the local Date/Time
  When setting up the Ubuntu, the intial setup of the server would be in the UTC date time. So to bring it in your region (with an intent to schedule a cron job) you can use the following commands in the reference article to set the date time of the server

  

  Reference:
  https://www.digitalocean.com/community/tutorials/how-to-set-up-time-synchronization-on-ubuntu-18-04

• Crontab/Scheduler (Windows)

  Crontab in Ubuntu is to schedule jobs which run at regular intervals. In Ubuntu there is a one system wide cron schedule file and one is user based. Sudo user are free to edit both based on their requirements and more about them can be explored at the following reference articles.

  Note: To use cron for tasks meant to run only for your user profile, add entries to your own user’s crontab file.

  

  

  Reference:
  https://help.ubuntu.com/community/CronHowto
  https://vitux.com/how-to-schedule-tasks-on-ubuntu-using-crontab/
  https://hostadvice.com/how-to/how-to-setup-a-cron-job-on-ubuntu-18-04/

• Environment Variables

  As in Windows we have the PATH variable and other Session/System variables, the Ubuntu universe have a similar setup well defined in the following article:

  

  https://help.ubuntu.com/community/EnvironmentVariables

Hope it helps.