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1.8 KiB
Linux Runlevels Guide
This document outlines the standard runlevels for Red Hat and Debian-based systems. Runlevels are used by init systems to define different states or modes of operation for the system.
📊 Runlevels Overview
| Runlevel | Description | Red Hat | Debian |
|---|---|---|---|
| 0 | Halt | ✅ Supported | ✅ Supported |
| 1 | Single User Mode | ✅ Supported | ✅ Supported |
| 2 | Multi-user (No Network) | ❌ (HaveNet) | ✅ Supported |
| 3 | Multi-user (Network, No GUI) | ✅ Supported | ✅ Supported |
| 4 | Custom/User Defined | ✅ Supported | ✅ Supported |
| 5 | Multi-user (GUI Mode) / Halt (err) | ❌ (GUI Mode) | ❌ (Halt/Error?) |
| 6 | Reboot | ✅ Supported | ✅ Supported |
💡 Note:
- On Red Hat, runlevel 5 typically starts the system with a graphical user interface (GUI).
- On Debian, runlevel 5 is often unused or reserved for custom setups.
- Runlevel behavior can be customized depending on system configuration.
🔧 Commands
Check Current Runlevel
runlevel
Change Runlevel
telinit <runlevel>
or
init <runlevel>
⚠️ Changing runlevels may stop or restart services. Use with caution, especially on production systems.
📚 Additional Tips
-
Modern Linux systems (especially systemd-based) may not rely on traditional runlevels. Instead, they use targets. Example:
systemctl get-default systemctl isolate graphical.target