pyrokinesisstudio/linux-introduction

Compilation of essential linux commands with examples

Simple and useful Linux commands

Baby Steps 👶

• learn how to use man <command>
• what are flags and the ones that are common across commands (-h, --help)
• ls -l and/or ls -la
• echo
• rmdir for empty directories
• touch to create 1 or more files
  • example:

    $ touch test1.txt test2.txt test3.txt
    $ mkdir test && mv test* test/
    

• cat to view a file
• (more), less, head and tail to view bigger files
• wc to know how big is a file (flags: -w words, -c bytes, -l lines)

Intermediate Steps 👦 👧

• mv and cp: rename or change place and copy (for files and directories)
• power of rm: be careful! To delete an entire directory rm -rf <dir>
• using * to delete or move multiple files CAREFUL
• Why is it important to learn how to move, delete and copy things from the command line?
• what is piping (|) and redirect (>, <)
• reading a file and using grep with a pipe to isolate context
• using the -B and -A flags with grep
• write to a file using echo with a redirect (- find and locate)

Advanced Steps 👨 👩

• download pages or documents using curl

  • examples:

    $ curl http://www.google.com //shows the whole page in stdin
    $ curl -I http://www.google.com //shows only headers
    $ curl -I http://www.foundersandcoders.com // header says 301
    // If we try to get the foundersandcoders.com page, we only see the html redirect page
    // Solution is to use the follow redirect flag (-L)
    $ curl -L http://www.foundersandcoders.com
    // The headers tell us that the location it redirected to is http://foundersandcoders.com
    // Both flags can be used to get the info of both pages
    $ curl -L -I http://www.foundersandcoders.com
    // Redirecting into a file
    $ curl -L http://www.foundersandcoders.com > FAC-Web.html
    // Isolating context using grep
    $ curl -L http://www.foundersandcoders.com |grep 'href="/' > FAC-links.txt
    // Using the -s flag to silence curl or the -# flag to change it to a progress bar
    // Go to https://github.com/EarthToAbigail/Scripts/blob/master/multi-enum.sh
    // Click on 'Raw' and grab the link
    $ curl -# https://raw.githubusercontent.com/EarthToAbigail/Scripts/master/multi-enum.sh > script.sh
    

• configuring shortcuts using alias in config files

  • show curl -# or wannaknow example

useful Networking commands:

Might need to install net-tools

• ifconfig to know what is your private ip

• ifconfig <interface> to monitor a specific interface

• nc or ncat to open network connections

  • examples:

  First Chat - Demo with Haydn

  First, on Haydn's computer:
    $ nc -l 4444
  
  On My computer:
    $ nc -nv <haydn's ip> 4444
  

  File Transfer - With Haydn or Locally

  Haydn's machine:
  $ nc -l 4444 > mynah.txt
  
  My machine:
  $ nc -nv <haydn's ip> 4444 < test.txt