10 Lazy Sysadmin Hacks to Supercharge Linux Efficiency

Technique 1: Unmount an Unresponsive DVD Drive

When a DVD device is busy, use fuser /media/cdrom to identify the holding process, then terminate it with fuser -k /media/cdrom before running eject to release the media.

Technique 2: Recover a Frozen Screen

If the terminal becomes garbled, simply execute reset. The command restores the display without rebooting the machine, saving time when you are logged in through multiple SSH hops.

Technique 3: Collaborative Screen Sessions

Use GNU screen to share a terminal with a colleague. Example workflow:

Switch to the colleague’s account: su - david SSH to the target host: ssh posh Create a named session: screen -S foo Invite the colleague: screen -x foo Both users can see and type commands simultaneously, facilitating joint debugging. Detach with Ctrl‑A D and re‑attach later using screen -x foo.

Technique 4: Recover a Forgotten Root Password

Reboot into GRUB, edit the kernel line (press E), append 1 to the end of the kernel parameters, and boot into single‑user mode. Then run: passwd Enter the new password, reboot, and log in with the updated credentials.

Technique 5: SSH Backdoor for Remote Support

Establish an SSH reverse tunnel from an internal machine ( ginger) to an external host ( blackbox.example.com) using:

ssh -R 2222:localhost:22 [email protected]

Keep the session alive, then from the external side connect back to the internal host: ssh -p 2222 root@localhost This creates a secure channel that bypasses the firewall for remote assistance.

Technique 6: Remote VNC Over SSH Tunnel

Start a VNC server on the internal host: vncserver -geometry 1024x768 -depth 24 :99 Forward the VNC port (5999) from the internal host to the external host, then from the external host to the client machine using a chain of -R and -L tunnels:

ssh -R 5999:localhost:5999 [email protected]   # on ginger
ssh -L 5999:localhost:5999 [email protected]   # on tech

Finally, launch the viewer: vncviewer localhost:99 Windows users can achieve the same with PuTTY’s port‑forwarding settings.

Technique 7: Bandwidth Measurement

Install iperf on both ends, start the server: /home/bob/perf/bin/iperf -s -f M and run the client:

/home/bob/perf/bin/iperf -c ginger -P 4 -f M -w 256k -t 60

Typical 1 GbE links show ~112 Mbit/s; bonding two NICs can reach ~220 Mbit/s. Use the results to verify expected throughput.

Technique 8: Command‑Line Scripting and Utilities

Generate a large /etc/hosts file with a single loop:

P=1; for i in $(seq -w 200); do echo "192.168.99.$P n$i"; P=$(expr $P + 1); done >>/etc/hosts

Check memory consistency across a cluster via SSH and awk:

for num in $(seq -w 200); do ssh n$num free -m | grep Mem | awk '{print $2}'; done | sort | uniq

The pipeline extracts total memory per node, sorts values, and removes duplicates.

Technique 9: Console Inspection

Read the virtual console device to see what is displayed on the physical console: cat /dev/vcs1 Replace 1 with other numbers for additional virtual terminals.

Technique 10: Random System Information Gathering

Collect CPU details: cat /proc/cpuinfo Count processors: cat /proc/cpuinfo | grep processor | wc -l Show disk usage: df -h Display BIOS information (requires root): dmidecode | less Check NIC driver and firmware:

ethtool -i eth0

Conclusion

Regularly sharing screen sessions, reading manual pages, and solving real problems are the best ways to become a faster, more efficient Linux administrator, freeing up time for personal interests.