20 Linux System Monitoring Tools

20 Linux  System Monitoring Tools Every SysAdmin Should Know

Need to monitor Linux server performance? Try these built-in command and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:

1. Finding out bottlenecks.
2. Disk (storage) bottlenecks.
3. CPU and memory bottlenecks.
4. Network bottlenecks.

#1: top - Process Activity Command

The top program provides a dynamic real-time view of a running system i.e. actual process activity. By default, it displays the most CPU-intensive tasks running on the server and updates the list every five seconds.

Commonly Used Hot Keys

The top command provides several useful hot keys:

Hot Key	Usage
t	Displays summary information off and on.
m	Displays memory information off and on.
A	Sorts the display by top consumers of various system resources. Useful for quick identification of performance-hungry tasks on a system.
f	Enters an interactive configuration screen for top. Helpful for setting up top for a specific task.
o	Enables you to interactively select the ordering within top.
r	Issues renice command.
k	Issues kill command.
z	Turn on or off color/mono

#2: vmstat - System Activity, Hardware and System Information

The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.


# vmstat 3
Sample Outputs:

Windows is not so secure ?

1.user can take ownership of any system files




open notepad.exe and type








Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\*\shell\runas]
@="Take Ownership"
"NoWorkingDirectory"=""
[HKEY_CLASSES_ROOT\*\shell\runas\command]
@="cmd.exe /c takeown /f \"%1\" && icacls \"%1\" /grant administrators:F"
"IsolatedCommand"="cmd.exe /c takeown /f \"%1\" && icacls \"%1\" /grant administrators:F"
[HKEY_CLASSES_ROOT\Directory\shell\runas]
@="Take Ownership"
"NoWorkingDirectory"=""
[HKEY_CLASSES_ROOT\Directory\shell\runas\command]
@="cmd.exe /c takeown /f \"%1\" /r /d y && icacls \"%1\" /grant administrators:F /t"
"IsolatedCommand"="cmd.exe /c takeown /f \"%1\" /r /d y && icacls \"%1\" /grant administrators:F /t"

save as *(any name).reg

invoke the file , this will patch windows registry . so their will be "take ownership" option in the context menu (appear on right click).

2. windows 7 system files can be easily modified .

So here is a list of various system files in Windows 7 which can be easily hacked using Resource Hacker:

Approx. all Windows 7 system icons

Login Screen Background -> %windir%\System32\imageres.dll

Login Screen image resources -> %windir%\System32\authui.dll

Startup Sound -> %windir%\System32\imageres.dll

Start ORB images -> %windir%\Explorer.exe -> Bitmap -> 6801 - 681
 2 -> %windir%\System32\imageres.dll