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Dan Higgins
Dan Higgins

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Day 3 of #30DaysRHCSAChallenge – Group Therapy (For Users, Not Me... Mostly)

📚 Table of Contents

The Real World Problem

"Why is this user part of six different groups? Are they building servers or starting a band?"

If you've ever stared at the output of groups and thought,

"Wait, what even is a 'secondary group'?"
then today's your kind of chaos.

Today’s Mission

  • Understand primary vs secondary groups (like best friends vs group chats you're stuck in)

  • Create groups manually

  • Add users to one or more groups

  • View group membership

  • Remove users from groups without deleting the group or starting a system-wide rebellion

Commands I Used (and promptly typo'd the first three times)

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Bonus spell: see all groups on the system:

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RHCSA Objectives Covered

  • Create and manage groups

  • Manage user group memberships

  • Understand primary and secondary group differences

  • Use commands like usermod, groupadd, groupdel, and gpasswd

What I Learned Today

  • The primary group is like your day job. The secondary groups are your side hustles.

  • usermod -aG is your friend — forget the -a and you accidentally wipe all other group memberships

  • getent group feels like snooping on everyone’s backstage passes

Real Life Analogy Time

If users are people in a company, then groups are:

  • devops_team – who gets access to deploy

  • finance – who sees the money stuff

  • lunch_club – okay this one’s unofficial but still important

Assign wisely. Because one wrong group and suddenly “Susan from HR” has root access to /var/www.

Tomorrow’s Challenge Teaser

“Wait… I thought that file belonged to me?”

Day 4 is all about ownership, permissions, and why chown is a blessing and a curse.

What’s your weirdest group name on your Linux box?
Mine’s kettlegang. Long story.

RHCSA #LinuxAdminLife #UserGroupDrama #30DaysChallenge #BeginnerToBoss #SysadminChronicles #RHEL9 #CommandLineConfidence #DevTo #KeepLearning #RealWorldRHCSA

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