Checking Multiple VNC Servers Running on Linux System

Checking Multiple VNC Servers Running on Linux System

This article will discuss how to check multiple VNC servers running on a Linux system. We will cover key concepts related to VNC servers and how to identify running instances on a Linux system.

What is VNC Server?

VNC (Virtual Network Computing) Server is a remote desktop sharing software that allows users to remotely access and control another computer over a network. In essence, it creates a virtual session of the desktop environment and enables users to access it from any device with VNC client software.

Why Check Running VNC Servers on Linux?

Checking running VNC servers on a Linux system is crucial for several reasons. It helps system administrators manage available resources and ensure efficient operation of the servers. Additionally, it can aid in troubleshooting connectivity issues or identifying potential security vulnerabilities.

Using Command Line to Check Running VNC Servers

The command line is an effective way to identify running VNC servers on Linux. Specifically, the ps and grep commands can be used together to filter and display running processes related to VNC servers.

The ps Command

The ps command lists active processes running on a Linux system. By itself, ps displays limited information about running processes. However, when combined with other commands like grep, it can display more detailed information about specific processes.

The grep Command

The grep command searches for a specified string in files or command output. When used with the ps command, it filters the output to display only the desired information.

Checking VNC Servers with the ps-ef|grep vnc Command

Combining the ps and grep commands to check VNC servers on Linux looks like this:

This command outputs a list of running VNC servers, displaying information such as the process ID (PID), command line arguments, and running time.

Understanding the Output

The output of the ps-ef|grep vnc command may appear as follows:

Here, each line represents a running VNC server instance. Let's break down the first line's details:

• user: the user who started the VNC server
• 1234: the process ID (PID) of the VNC server
• 1: the parent process ID (PPID) of the VNC server, typically 1 for system processes
• 0: the process status
• 10:00: the start time of the VNC server
• ?: the controlling terminal
• 00:00:05: the total CPU time used by the VNC server

Interpreting the Output

Interpreting the output of the ps-ef|grep vnc command involves understanding parameters such as the display number and port number. These identify individual VNC server instances.

Display Number

The display number in a VNC server output indicates which desktop session the VNC server is controlling. Display numbers typically follow the format of :n, where n is a positive integer. In our example output, the display number is :1.

Port Number

Port numbers are associated with specific VNC server instances and indicate the port on which the VNC server is listening for connections. In our example output, the port number is 5901.

Identifying Exact Port Running

In some cases, the port number may not be apparent in the ps-ef|grep vnc output. One approach to identify the exact port number is to examine the VNC server configuration file, typically located in the user's home directory, e.g., /home/user/.vnc/xstartup.

• VNC Server is a remote desktop sharing software that allows users to remotely access and control another computer over a network.
• The ps and grep commands can display running VNC servers on a Linux system.
• Understanding the output involves interpreting parameters such as display numbers and port numbers.
• Examining the VNC server configuration file can help identify the exact port number for each server instance.

References

• RealVNC Documentation
• Installing and Configuring VNC on Ubuntu 18.04
• Linux ps Command Manual
• Linux grep Command Manual