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2025-02-11
Tired of system crashes, broken packages, or sluggish performance? We’ve compiled the ultimate Linux Troubleshooting Guide to help you tackle any issue like a seasoned sysadmin. Here are 10 critical areas covered in this guide:
1. Boot Issues
- GRUB Errors: Use `grub-install` and `update-grub` to fix GRUB issues.
- Kernel Panics: Boot into recovery mode and use `fsck` to check and repair the file system.
- Boot Failures: Use `systemctl reboot` or `reboot` to restart the system.
2. User & Login Problems
- Recover Lost Root Passwords: Boot into single-user mode and use `passwd` to reset the root password.
- SSH Access Issues: Check SSH configuration with `sshd -t` and restart the service with
systemctl restart sshd.
3. File System Errors
- Disk Space Management: Use `df -h` to check disk usage and `du -sh *` to find large files.
- Repair Read-Only File Systems: Remount the file system with
mount -o remount,rw /.
4. Networking Hiccups
- Restore Internet Access: Use `ifconfig` or `ip addr` to check network interfaces and `ping` to test connectivity.
- Troubleshoot Wi-Fi and DNS: Use `nmcli` for network management and `nslookup` for DNS issues.
5. High CPU & Memory Usage
- Identify Resource-Hogging Processes: Use `top` or `htop` to monitor processes.
- Optimize Performance: Use `nice` and `renice` to adjust process priorities.
6. Package Management Issues
- Resolve Broken Dependencies: Use `apt-get install -f` or
yum-complete-transaction. - Slow Installations: Use local mirrors or `apt-cacher-ng` to speed up package installations.
7. Security Fixes
- Detect Unauthorized Access: Use `last` and `lastb` to check login attempts.
- Configure Firewalls: Use `ufw` or `iptables` to manage firewall rules.
- Block Brute-Force Attacks: Use `fail2ban` to block repeated failed login attempts.
8. Service & Daemon Failures
- Restart Failing Services: Use
systemctl restart <service>. - Resolve Port Conflicts: Use `netstat -tuln` to check used ports.
9. Kernel & Driver Problems
- Fix Module Errors: Use `modprobe` to load kernel modules.
- Missing Drivers: Use `lspci` and `lsmod` to identify and install missing drivers.
10. Backup & Recovery
- Restore Deleted Files: Use `extundelete` or
testdisk. - Create Full System Backups: Use `rsync` or `dd` for backups.
What Undercode Say
Linux troubleshooting is an essential skill for any sysadmin or IT professional. Mastering these commands and techniques ensures you can handle most issues that arise in a Linux environment. Here are some additional commands and tips to enhance your troubleshooting skills:
- System Logs: Use `journalctl` to view system logs and diagnose issues.
- Network Troubleshooting: Use `traceroute` and `mtr` to diagnose network paths and latency.
- Disk Health: Use `smartctl` to check the health of your disks.
- Process Management: Use
kill,pkill, and `killall` to manage processes. - File Permissions: Use `chmod` and `chown` to manage file permissions and ownership.
- Service Management: Use `systemctl` to manage services and daemons.
- Package Management: Use
apt,yum, or `dnf` to manage software packages. - Security Auditing: Use `lynis` for system security auditing.
- Backup Solutions: Use `Bacula` or `Amanda` for comprehensive backup solutions.
- Performance Monitoring: Use `sar` and `vmstat` for system performance monitoring.
For more detailed guides and tutorials, visit:
By mastering these commands and techniques, you can ensure your Linux systems run smoothly and efficiently. Happy troubleshooting!
References:
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