Getting comfortable with Linux

As a pentester most of the times you work on a linux destro and it important that you have the basics right so that you do not search for the commands every-time you try to do something. Best is to train yourself on linux 1st before you get into this side.

I will try to keep this concise and keep updating it as & when I can think of something:

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Common Internet Searches from the terminal :)
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[A] Google search:

    firefox www.google.com/search?q=Harshwardhan\ Kamdi
        (Use the '\' seperator to continue the query. If the '\' seperator is not used then each word seperated by space will be treated as a new website. For e.g. in above example if the '\' is not used then firefox will open google and search for Harshwardhan and then it will open another tab and search for Kamdi.com ;))

    Blah Blah Blah.....
        Found a much easier way - Enter the following code in a terminal:
            google() {     search="";     echo "Googling: $@";     for term in $@; do         search="$search%20$term";     done;     xdg-open "http://www.google.com/search?q=$search"; }

            ===> Once done then keep searching from the terminal as : google "query"   :)

        Google "Search query"
        For Example: google "This is my search" and Hurrah.. this will open the default browser and search for it :)


[B] Youtube search:
    www.youtube.com/results?search_query=this

[C] Opening a Private browsing session?
    Terminal > firefox --private

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Symbolic link
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Problem: After installing my fav text editor - Sublime there was no way to launch it from the terminal...
Solution: Add a symbolic link

sudo ln -s /opt/sublime_text/sublime_text /usr/local/bin/sublime

Now the sublime text editor can be launched from the terminal by simply typing 'Sublime'

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Check and Kill Running Processes:
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1. List the running Processes                 ps aux
2. Check running processes from a user        ps aux |grep 'username'  or ps -ef | grep 'username'
3. To kill a Processes                         pkill "process name" for e.g. pkill firefox  if there are multiple instances then killall firefox

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Finding Files
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https://help.ubuntu.com/community/FindingFiles

find / -type f -name "" would do the trick if you know exact filename.
find / -type f -iname "filename*" if you want to match more files.

locate some-file.avi searches through a database(s) that is maintained of almost every file on the disk, for a file called "some-file.avi"
locate -i "some-file.avi" will ignore the case of the file you are searching for.
locate -i "*.txt" will display a list of location of all the files with *.txt extension on your system.

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Checking Installed programs and packages
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dpkg --get-selections | grep -v deinstall
dpkg --get-selections | grep -v deinstall > ~/Desktop/packages   ----> To get the list of installed packages in a file.

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Scheduled Tasks
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https://help.ubuntu.com/community/CronHowto

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Deleting 1 line at a time in nano editor
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Go to the beginning of the line and press 'ctrl + K'

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Encoding and Decoding in Base64

Many times during pentesting you will get some text that is encoded in base64 which you want to decode quickly - like tracing a SAML token or trying to see if there is some hidden gem in it !!!''

At times while uploading a reverse shell you may want to encode your string with base64.

While there are tons of ways in which this can be done e.g. Notepad++ plugin etc however the quick and handy from the terminal of your linux box is 'openssl'

To Encode:

openssl base64 -e <<< 'Welcome to Pentestknights blog'

To Decode:

openssl base64 -d <<< encoded text