10 Lazy Sysadmin Tricks to Boost Linux Efficiency in Minutes

A skilled Linux system administrator can accomplish in ten minutes what others might need two hours for, and this guide shares ten essential, "lazy" tricks to boost efficiency.

1. Unmount an unresponsive DVD drive

Mount the DVD, start a dummy loop, then try to eject. When the device is busy, use fuser to find the owning process and kill it.

# mount /media/cdrom<br># cd /media/cdrom<br># while [ 1 ]; do echo "All your drives are belong to us!"; sleep 30; done

# eject

# fuser /media/cdrom

# fuser -k /media/cdrom

# eject

2. Recover a stuck screen

When the terminal becomes garbled, use reset (not reboot) to restore normal output.

# cat /bin/cat

# reset

3. Screen collaboration

Share a terminal session with a colleague using screen. Create a session, attach to it, and detach with Ctrl‑A D.

# su - david

# ssh posh

# screen -S foo

# screen -x foo

Detach: Ctrl‑A D. Re‑attach later with screen -x foo.

4. Recover a forgotten root password

Reboot, edit the GRUB entry, append 1 to the kernel line, boot into single‑user mode, and run passwd to set a new root password.

# passwd

5. Create an SSH backdoor

Establish a reverse SSH tunnel through a publicly reachable host (blackbox.example.com) so that an external support machine can reach an internal server.

Verify policy and obtain permission.

On the internal server (ginger) run: # ssh -R 2222:localhost:22 [email protected] Keep the session open, then on the support machine connect: # ssh [email protected] From the support machine, reach the internal server: # ssh -p 2222 root@localhost Enter the internal root password when prompted.

Both parties can now work together, optionally using screen for shared sessions.

6. Remote VNC via SSH tunnel

Start a VNC server on the internal host, forward the VNC port through the same reverse tunnel, then forward it back to the support machine.

# vncserver -geometry 1024x768 -depth 24 :99

# ssh -R 5999:localhost:5999 [email protected]

# ssh -L 5999:localhost:5999 [email protected]

# vncviewer localhost:99

Windows users can achieve the same with PuTTY; see the screenshot.

7. Check network bandwidth

Compile and run iperf on both ends to measure throughput.

# wget http://dast.nlanr.net/Projects/Iperf2.0/iperf-2.0.2.tar.gz<br># tar zxvf iperf*gz<br># cd iperf-2.0.2<br># ./configure -prefix=/home/bob/perf<br># make<br># make install

# /home/bob/perf/bin/iperf -s -f M

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

8. Command‑line scripts and utilities

Use loops, awk, grep, and sed to automate tasks such as generating a large /etc/hosts file or checking memory across many nodes.

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

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

9. Console inspection

Read the virtual console devices to see what is displayed on a remote machine’s console.

# cat /dev/vcs1

10. Random system information collection

Gather CPU, disk, BIOS, and NIC firmware details using standard commands.

# cat /proc/cpuinfo

# cat /proc/cpuinfo | grep processor | wc -l

# df -h

# dmidecode | less

# ethtool -i eth0

By sharing screens, reading manual pages, and constantly solving problems, administrators can become faster, more reliable, and free up time for other interests.