Troubleshooting Common Linux Problems: A Practical Guide

[Lomanu4]

Table of Contents

• 
  Start with the Basics: What’s Really Going On?
  
  
• 
  System Logs: Your First Detective Tool
  
  
• 
  Resource Hogs: CPU, Memory, and Disk Issues
  
  
• 
  Permission Headaches and Dependency Drama
  
  
• 
  Network Not Working? Step-by-Step Fixes
  
  
• 
  Boot Issues and Frozen Systems
  
  
• 
  Real-World Scenarios and Quick Solutions
  
  
• 
  Wrapping Up
  

Start with the Basics: What’s Really Going On?

Before you dive into commands, take a breath and gather the facts.

• 
  What’s broken? Is there an error message?
  
  
• 
  Did something change recently (updates, new installs)?
  
  
• 
  Can you reproduce the problem, or is it random?
  

Asking the right questions and getting a clear description of the issue saves you hours of wild goose chases


System Logs: Your First Detective Tool

Logs are your best friends when Linux acts up.

• 
  General system logs:
  tail -n 50 /var/log/syslog or tail -n 50 /var/log/messages
  
  
• 
  Kernel messages:
  sudo dmesg | tail -20
  
  
• 
  Authentication issues:
  tail -n 50 /var/log/auth.log or /var/log/secure
  
  
• 
  Boot problems:
  cat /var/log/boot.log or use head/tail for quick peeks**
  
  
• 
  Pro tip: Use grep "error" to search for red flags fast
  

Resource Hogs: CPU, Memory, and Disk Issues

Is your system sluggish or unresponsive?

• Check system load:

uptime shows load averages

• See what’s eating resources:

top, htop, or ps aux --sort=-%cpu | head for CPU hogs
ps aux --sort=-%mem | head for memory guzzlers

• Disk space:

df -h for usage, du -sh * to find big files, and
sudo apt clean or sudo dnf clean all to clear package caches.

• If a process is out of control, use kill -9 PID (replace PID with the process ID).

Permission Headaches and Dependency Drama

Permission denied?

• 
  Check with ls -la filename
  
  
• 
  Fix with chmod +x filename or change ownership with chown
  user:group filename.
  

Missing libraries or dependencies?

• For errors like “libsomething.so.2: cannot open shared object file,” use:

apt-file search libsomething.so.2 (Debian/Ubuntu)
dnf provides */libsomething.so.2 (Fedora/RHEL)

• Install the required package with your package manager

Network Not Working? Step-by-Step Fixes

• 
  Check your network interface:
  ip link
  
  
• 
  Verify your IP address:
  ip addr
  
  
• 
  Can you reach your gateway?
  ip route show and ping -c 4
  
  
• 
  Test DNS:
  ping -c 4 google.com
  
  
• 
  Check open ports:
  nc -zv google.com 443.
  
  
• 
  If SSH locks you out, try accessing the server locally or through the console, and check for high load or network failures
  

Boot Issues and Frozen Systems

• 
  Boot failures:
  Check /var/log/boot.log for clues.
  Use dmesg for kernel and hardware errors.
  
  
• 
  Frozen system?
  Try switching TTYs with Ctrl+Alt+F2, or use the hypervisor console if it’s a VM.
  
  
• 
  Safe reboot:
  If all else fails, use echo b > /proc/sysrq-trigger for a safe reboot
  

Real-World Scenarios and Quick Solutions

Script works manually but fails in cron?

• 
  Add logging to your script.
  
  
• 
  Compare environment variables between manual and cron runs.
  
  
• 
  Fix missing PATH or variables in your script.
  
  
• 
  Intermittent network drops?
  
  
• 
  Check logs for hardware errors.
  
  
• 
  Monitor with ping or dmesg -w for real-time clues
  

Wrapping Up

Linux troubleshooting is all about staying calm, asking the right questions, and using the right tools.

• 
  Always check logs first.
  
  
• 
  Monitor your resources.
  
  
• 
  Don’t ignore permissions or dependencies.
  
  
• 
  Automate what you can, but know how to dig in manually.
  
  
• 
  And remember, the Linux community is massive-don’t be afraid to
  search forums and share your own solutions. Happy troubleshooting!
  

Пожалуйста Авторизируйтесь или Зарегистрируйтесь для просмотра скрытого текста.