#techtipthursday — Public Fediverse posts

#TechTipThursday: something's already on port 8080 and you don't know what.

ss -tulpn

Sockets, TCP, UDP, listening, with process name and PID. One command and you know exactly what's squatting on the port.

netstat's been deprecated for years. ss is faster and already installed.
#Linux #SysAdmin

#TechTipThursday: when your #storage is full and you have no idea what ate it. df tells you the partition is at 100 percent. It doesn't tell you exactly where. For that, install ncdu and run it on the directory you want to inspect:

ncdu /var

It scans the disk and gives you an interactive, sorted view of what's taking up space. Arrow keys to move around, enter to drop into a folder, and you drill straight down to the giant log file or the forgotten backup that filled the drive.
#Linux #SysAdmin

#TechTipThursday: the Linux trick that saves you from retyping the whole command.

You run something, the terminal says permission denied, and you realize you forgot sudo. Instead of pressing up and cursoring all the way to the front of the line, just type:

sudo !!

The double bang means "the last command I ran," so this reruns it with sudo in front. Small thing, but you'll reach for it constantly.

#TechTipThursday: find out if your Linux box actually needs a reboot.

After a round of updates the guessing game is always the same. Do I need to reboot, or can I keep working? On Fedora and RHEL based systems, stop guessing:

needs-restarting -r

It checks whether the kernel or core libraries changed and tells you straight up whether a reboot is required. It lives in the dnf-utils package, so install that first if you don't have it.

#Linux #SysAdmin #Fedora #RHEL #CLI

#TechTipThursday

The best time to learn a new Linux tool is when nothing is on fire.
Pick one command you use often and go one level deeper this week.

Already use grep? Try grep -r, grep -v, grep -E.
Already use find? Add -exec to actually do something with the results.
Already use systemctl? Try systemctl list-dependencies.

You don't need a course. You need 20 minutes and a test machine. man is still the best documentation that exists.

#Linux #SysAdmin #LearningLinux #TechTip

Need to find a file fast on Linux?

Search by name: find /path -name "filename"
Search by content: grep -r "search term" /path
Find recently modified files: find /path -mtime -1

The file is there. You just have to know how to look.
#TechTipThursday #Linux #SysAdmin #TechTip #OpenSource

#TechTipThursday

Know what's on your disks before your disks tell you the hard way.
Check disk usage: df -h
See what's eating your space: du -sh /* 2>/dev/null | sort -rh | head -10
List block devices: lsblk
Disks don't fail with warning. They fail at the worst possible moment.

#Linux #SysAdmin #DiskManagement

Permissions are the backbone of Linux security. Know these cold:

Add a user to a group: usermod -aG groupname username
Check what groups a user belongs to: groups username
Change file ownership: chown user:group filename

"Just chmod 777 it" is not a permissions strategy. It's a cry for help.
#Linux #SysAdmin #Permissions #TechTip #TechTipThursday

#TechTipThursday: a few journalctl commands worth keeping handy on Rocky Linux.

journalctl -b -- current boot only
journalctl -f -- follow in real time
journalctl -u sshd -- filter by service
journalctl -p err -- errors and above

#RockyLinux #Linux #SysAdmin #systemd

#TechTipThursday
Package management is one of those things every Linux admin should know cold.

Search for a package:
dnf search packagename

Install it:
dnf install packagename

Check what's installed:
rpm -qa | grep packagename

Remove it cleanly:
dnf remove packagename

Your package manager is your best friend. Treat it accordingly.
#Linux #SysAdmin #PackageManagement #TechTip #RHEL #RockyLinux

#TechTipThursday: SELinux is enabled by default on Rocky Linux. Before you disable it, learn what it's telling you.

getenforce -- check current mode
sudo ausearch -m avc -ts recent -- see recent denials
sudo sealert -a /var/log/audit/audit.log -- human-readable denial explanations
sudo setenforce 0 -- permissive mode for troubleshooting only

Learning to read SELinux logs beats turning it off every time.
#RockyLinux #Linux #TechTipThursday #SELinux #SysAdmin

SSH is how you get things done remotely. Know it cold.
Connect to a remote host: ssh user@hostname
Copy files securely: scp file.txt user@hostname:/path/
Generate SSH keys: ssh-keygen -t ed25519

Passwords are fine. Keys are better. Use keys.
#Linux #SysAdmin #SSH #Security #TechTip #TechTipThursday

Keep a specific package version pinned on Rocky Linux with dnf versionlock.

Install the plugin if you haven't:
sudo dnf install python3-dnf-plugin-versionlock

Then:
sudo dnf versionlock add <package> -- lock it
sudo dnf versionlock list -- see what's pinned
sudo dnf versionlock delete <package> -- release the lock

Handy for holding a kernel, database, or app version steady while everything else updates.
#RockyLinux #Linux #TechTipThursday #SysAdmin

#TechTipThursday

Your Linux host is only as secure as you make it.
Check who's logged in right now: who
See open network connections: ss -tulnp

Check for listening services you don't recognize:
systemctl list-units --type=service --state=running

If you can't explain why a service is running, that's your homework.
#Linux #SysAdmin #Security #TechTip

Here's a few dnf commands that are easy to overlook but genuinely useful on Rocky Linux:

dnf history -- full log of installs and removals with timestamps
dnf autoremove -- removes packages nothing depends on anymore
dnf provides <file> -- find out which package owns a specific file
dnf repoquery --installed -- everything currently on your system

What's your go-to dnf command? Share it in the replies.
#RockyLinux #Linux #TechTipThursday #SysAdmin #OpenSource

Networking on Linux isn't magic. It just looks that way until you know where to look!

Check your network interfaces: ip addr show
Test connectivity: ping -c 4 google.com
Check your routing table: ip route show

#TechTipThursday #Linux #SysAdmin

#TechTipThursday
Printers. The final boss of Linux administration. Check your print service is running:
systemctl status cups

List available printers:
lpstat -p

Send a file to the printer and pray:
lp filename.pdf

Linux has conquered the cloud, the kernel, and the enterprise. Printers remain undefeated.

#TechTipThursday
Yes, Linux admins still configure email. No, it never gets less weird.

Check if your mail service is running:
systemctl status postfix

Send a test email from the command line:
echo "Test" | mail -s "Hello" [email protected]

Check the mail queue:
mailq

Nobody gets excited about email configuration. Until something breaks and logs stop delivering. Then it's the only thing that matters.

Check your system logs:
journalctl -xe

Follow logs in real time:
journalctl -f

Filter by service:
journalctl -u nginx

Logs tell you everything, if you know where to look.
#SysAdmin #Linux #TechTipThursday

Check your system time and timezone:
timedatectl status

Set your timezone:
timedatectl set-timezone America/Chicago

Sync with NTP:
timedatectl set-ntp true

Getting time right matters more than people think, especially for logs, cron jobs, and anything distributed.

#TechTipThursday #linux #sysadmin

#TechTipThursday
Want to check or change your system locale on Linux?
localectl status

To list available locales:
localectl list-locales

To set one:
localectl set-locale LANG=en_US.UTF-8

Handy when you're deploying systems for users in different regions or when something's outputting dates and currencies in a format that makes no sense to you.
#linux #sysadmin

Quick cron reminder on this #TechTipThursday

*/5 * * * *
Runs every 5 minutes.

But remember: cron doesn’t care if the previous job finished. Long-running jobs can pile up fast. Sometimes a systemd timer is the better tool.

#Linux #Cron #SysAdmin #DevOps

Linux has solid built-in accessibility features:

On GNOME:
Settings → Accessibility

You’ll find:
- Screen reader (Orca)
- High contrast mode
- Zoom
- Large text scaling

Accessibility isn’t niche. It’s good engineering.

#TechTipThursday #Linux #Accessibility #OpenSource

#TechTipThursday

Running Wayland and something feels off? Try checking:
echo $XDG_SESSION_TYPE

If it says wayland, you’re native. If it says x11, you’re still on X.

Knowing which session you’re in saves a lot of confusion.

#Linux #Wayland #SysAdmin

If you’re writing shell scripts, start adding this:

set -euo pipefail

It forces your script to:
• Exit on errors
• Fail on unset variables
• Catch broken pipes

Small line. Big reliability boost.

#TechTipThursday #Linux #ShellScripting #SysAdmin

Don't sleep on built-in shell features:

* Ctrl+r for reverse history search
* Tab completion for paths and commands
* Brace expansion: mkdir project/{logs,data,tmp}

Master the shell you already use before adding new tools.

#TechTipThursday #Linux #SysAdmin

🔍 Tech Tip Thursday

If you inherit a server, do this first:
- List running services
- Identify owners (or admit there aren’t any)
- Document before touching anything

Future you will be grateful.

#TechTipThursday #Linux #SysAdmin #OpsLife

Quick self-audit you can do in under 15 minutes:

- List running services
- Ask: “Do I still need this?”
- Disable or document anything you forgot existed

Less running = less risk.

#TechTipThursday #Linux #SysAdmin #SecurityBasics

🔍 When’s the last time you audited your stack?

Removed stale services? Revoked unused credentials? Updated firewall rules? Reviewed crontabs & timers?

Clean servers = secure servers. Start 2026 with a clean slate!

#SysAdmin #LinuxTips #SecurityFirst #TechTipThursday