Operating Systems

Hard drive speed test using Linux command line and hdparm

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I will use /dev/sdc as our testing block device.
Note that all tests should be run multiple times and average time should be calculated to get more accurate result.

Bypassing hard drive’s buffer cache memory thus reading directly from the disk.

Read data from the second half of the disk that is if the hard drive size is 100GB.

To obtain cached reads run the following command:

Tcpdump Best Practices

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List of interfaces on which tcpdump can listen:


Listen on interface eth0:

Listen on any available interface :

Be verbose while capturing packets:

More verbose while capturing packets:

Very verbose while capturing packets:

Verbose and print the data of each packet in both hex and ASCII, excluding the link level header:

Verbose and print the data of each packet in both hex and ASCII, also including the link level header:

Less verbose (than the default) while capturing packets:

Limit the capture to 100 packets:

Record the packet capture to a file called capture.cap:

Record the packet capture to a file called capture.cap but display on-screen how many packets have been captured in real-time:

Display the packets of a file called capture.cap:

Display the packets using maximum detail of a file called capture.cap:

Display IP addresses and port numbers instead of domain and service names when capturing packets

Capture any packets where the destination host is 192.168.5.1. Display IP addresses and port numbers:

Capture any packets where the source host is 192.168.5.1. Display IP addresses and port numbers:

Capture any packets where the source or destination host is 192.168.5.1. Display IP addresses and port numbers:

Capture any packets where the destination network is 192.168.5.0/24. Display IP addresses and port numbers:

Capture any packets where the source network is 192.168.1.0/24. Display IP addresses and port numbers:

Capture any packets where the source or destination network is 192.168.5.0/24. Display IP addresses and port numbers:

Capture any packets where the destination port is 23. Display IP addresses and port numbers:

Capture any packets where the destination port is is between 1 and 1023 inclusive. Display IP addresses and port numbers:

Capture only TCP packets where the destination port is is between 1 and 1023 inclusive. Display IP addresses and port numbers:

Capture only UDP packets where the destination port is is between 1 and 1023 inclusive. Display IP addresses and port numbers:

Capture any packets with destination IP 192.168.1.1 and destination port 23. Display IP addresses and port numbers:

Capture any packets with destination IP 192.168.5.1 and destination port 80 or 443. Display IP addresses and port numbers:

Capture any ICMP packets:

Capture any ARP packets:

Capture either ICMP or ARP packets:

Capture any packets that are broadcast or multicast:

Capture 500 bytes of data for each packet rather than the default of 68 bytes:

Capture all bytes of data within the packet:

 

Microsoft Cognitive Services

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Microsoft Cloud Services

Vision,
Computer Vision,
Content Moderator,
Emotion,
Face,
Video,
Speech,

Bing Speech,
Custom Speech Service,
Speaker Recognition,
Language,

Bing Spell Check,
Language Understanding,
Linguistic Analysis,
Text Analytics,
Translator,
WebLM,
Knowledge,

Academic,
Entity Linking,
Knowledge Exploration,
QnA Maker,
Recommendations,
Search,

Bing Autosuggest,
Bing Image Search,
Bing News Search,
Bing Video Search,
Bing Web Search,

Windows Routing commandline

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Example 1


Persistent route


Delete Route 

 

Windows Commandline

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  • Making a Symbolik Link Command Line Windows

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Linux Sound Card HDMI problems

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1.  How can I change the default audio device from command line?

  • Normally Gui of Ubuntu allows you to do that  (System->Preferences->Sound), like the default input/output device and setting the volume.

      If that not works

2. Use The AlsaMixer 

kutayzorlu.com alsamixer HDMI configuration

F1 – Help
F2 – System Information
F6 – Select Sound Card
Esc – Exit the menu

3. Show the all of the sound devices 

Other Option list cards

4. Change it from GRUB

5. Change the config files and test it by Command Line

Reconfigure again for sound-base

 

Restart PC test again,  It works on my pc.

This test is very important to find which sound card you need to use,   1, and 3   is important  first is  Device  other is  port.