Unix

Unix is the name of a popular open source operating system.

Commands

^[1]

System Info

whoami

finger

man

date

cal

uptime

Searching Filesystem

grep

12 Practical Examples of Linux grep Command: https://www.tecmint.com/12-practical-examples-of-linux-grep-command/

locate

find

^[2]

whereis

which

Port Scanning

By default Nmap does a standard TCP SYN scan on the top 1000 ports of host. I never really use this by itself, get verbose output using "-vv" argument:

nmap -vv host

Nmap accepts target specification in loads of different formats including plain IP addresses, CIDR ranges and dash notation

nmap hostname

-or-

nmap 123.123.123.1–255

If you just want to find which hosts are alive, you can perform a ping scan with "-sn" argument:

nmap -sn 123.123.123.1/24

In some casess, a given host may disallow ping, so skipping "ping checks" can be done using "-Pn":

nmap -Pn <HOSTNAME|IP_ADDRESS>

To scan specific port ranges (i.e. outside the default/common 1000 ports scanned), use:

nmap -p 1–65535 <HOSTNAME|IP_ADDRESS>

Discover OS version with "-O" argument, and what service(s) are runnign using "-sV" which takes a "version-intensity" where 0 is a lower accuracy but fast/shallow scan, and 9 is a maximum accuracy but slow/deep scan:

nmap -sV — version-intensity 9 -O <HOSTNAME|IP_ADDRESS>

Find specific security vulnerabilities using the ".nse" scripts that come installed with the nmap tool:

 nmap --script=smb-vuln-cve-2017–7494 <HOSTNAME|IP_ADDRESS>

Lastly, Firewalls can attempt to be circumvented (or at least probed) using: ^[3] ^[4]

Files & Directories

cd

pwd

mkdir

rm

ls

lsof

lsof command: https://www.tutorialspoint.com/unix_commands/lsof.htm

ln

mv

cp

scp

scp command Tutorial: https://garron.me/en/articles/scp.html

rsync

Using rsync to synchronize a local and remote directory: http://bencane.com/2014/01/07/using-rsync-to-synchronize-a-local-and-remote-directory/

Text Output & String Operations

cat

more

head

tail

sed

Stream Editor (SED) is a command/tool which allows you to filter and transform text from the command line.

SED: https://www.gnu.org/software/sed/manual/sed.html

^[5] ^[6] ^[7] ^[8] ^[9] ^[10] ^[11] ^[12]

cut

CUT: http://www.manpagez.com/man/1/cut/

^[13]

File Permissions

chmod

Change file or folder permissions. EXAMPLE:

chmod 755 SomeFile.csv.zip

755 = Read for Everyone, Write for Owner and Group, Execute for Owner and Group

chown

Change the owner of a file. EXAMPLE:

chown SomeUser SomeFile.csv.zip

Linux and Unix chown command: http://www.computerhope.com/unix/uchown.htm

Text Editors

vi

vi Cheat Sheet: http://www.lagmonster.org/docs/vi.html^[14]^[15]
Notepad++ Unix to DOS line endings: http://www.larshaendler.com/2013/06/10/notepad-unix-to-dos-line-endings/ (don't forget to convert any Windows-based line endings/formatting before pasting into a Shell terminal within VI, or problems will occur)

^[16] ^[17]

Tools

cygwin: https://cygwin.com | MIRRORS (that Linux/Unix CLI feeling, on Windows)^[19]^[20]
chmod - calculator: http://www.onlineconversion.com/html_chmod_calculator.htm
PsTools ("ps" command for windows): http://technet.microsoft.com/en-us/sysinternals/bb896649.aspx
Find which process is running on a specific port: http://zakaria.se/knwoledge_base/find_which_process_is_running_on_a_specific_port.html
Top Ten Unix/Linux Distributions: http://distrowatch.com/dwres.php?resource=major

Resources

TLDR pages: https://tldr.sh | DEMO (simplified & community-driven man pages)^[21]
Unix and Linux System Administration Handbook (BOOK): http://www.goodreads.com/book/show/8772005-unix-and-linux-system-administration-handbook-4-e
Unix/Linux Command Cheat Sheet: http://fosswire.com/post/2007/08/unixlinux-command-cheat-sheet/
DOS-2-Unix (for windows): http://sourceforge.net/projects/dos2unix/ (convert Windows newline/special characters to Unix equivalent)
Dos2Unix / Unix2Dos (for Unix): http://waterlan.home.xs4all.nl/dos2unix.html (Text file format converters)^[22]
Unix Toolbox: http://cb.vu/unixtoolbox.xhtml
TMUX - A guide to increase your Unix productivity: http://apiumtech.com/blog/tmux-cheat-sheet-tips-tricks/

Tutorials

Unix tutorial: http://www2.ocean.washington.edu/unix.tutorial.html
Learn Enough Command Line to Be Dangerous: https://www.learnenough.com/command-line-tutorial
Bash Guide for Beginners: http://tldp.org/LDP/Bash-Beginners-Guide/html/index.html
Shell Scripting Primer: http://developer.apple.com/library/mac/#documentation/OpenSource/Conceptual/ShellScripting/Introduction/Introduction.html
How to run .sh file Shell Script in UNIX: http://www.cyberciti.biz/faq/run-execute-sh-shell-script/ (when "./" won't work)
How to redirect (Linux/Unix) console output to a file AND stdout: http://stackoverflow.com/a/418899/335867
Convert camelCase to underscores (camel_case) using sed: http://www.commandlinefu.com/commands/view/2038/convert-camelcase-to-underscores-camel_case
How to Create, Update and Remove Soft link in UNIXRead more: http://javarevisited.blogspot.com/2011/04/symbolic-link-or-symlink-in-unix-linux.html
How to Find and Delete Broken Symlinks on Linux: https://www.howtogeek.com/698838/how-to-find-and-delete-broken-symlinks-on-linux/
Display timestamp in dd/mm/yyyy_hh:mm:ss:ms in Unix or Linux: https://unix.stackexchange.com/questions/45926/display-time-stamp-in-dd-mm-yyyy-hhmmssms-in-unix-or-linux
How To Use chmod and chown Command: https://www.cyberciti.biz/faq/how-to-use-chmod-and-chown-command/ (remmbers its always of the format chown USER:GROUP)
Recursive chown starting with the directory above current directory: https://askubuntu.com/questions/631534/recursive-chown-starting-with-the-directory-above-current-directory (use the command "sudo chown -R USER:USER <FILE_OR_DIRECTORY>")
How to remove a single line from history?: https://unix.stackexchange.com/questions/49214/how-to-remove-a-single-line-from-history
How can I assign the output of a command to a shell variable?: https://unix.stackexchange.com/questions/16024/how-can-i-assign-the-output-of-a-command-to-a-shell-variable#16027
Bash -- double equals vs -eq: https://unix.stackexchange.com/questions/16109/bash-double-equals-vs-eq
How can I make chown work recursively?: https://superuser.com/questions/260925/how-can-i-make-chown-work-recursively
My Favorite Command-Line Shortcuts: https://henrikwarne.com/2018/08/11/my-favorite-command-line-shortcuts/ (escaped-dot = last typed part of command, CTRL+a = Move to the beginning of the line, CTRL+e = Move to the end of the line, CTRL+u = Clear the text on the line before current position, CTRL+w = Delete the word before cursor position)
Make cd follow symbolic links: https://unix.stackexchange.com/questions/55713/make-cd-follow-symbolic-links
What Is the Unix Epoch, and How Does Unix Time Work?: https://www.howtogeek.com/759337/what-is-the-unix-epoch-and-how-does-unix-time-work/

External Links

wikipedia: Unix
wikipedia: Hosts (file)
wikipedia: List of Unix commands
AT&T Archives -- The UNIX Operating System: https://www.youtube.com/watch?v=tc4ROCJYbm0
Running a shell script through Cygwin on Windows: https://stackoverflow.com/questions/15736898/running-a-shell-script-through-cygwin-on-windows
Chapter 2. Starting Off With a Sha-Bang: http://tldp.org/LDP/abs/html/sha-bang.html
What is the preferred Bash shebang?: https://stackoverflow.com/questions/10376206/what-is-the-preferred-bash-shebang
Commenting in BASH script: https://stackoverflow.com/questions/1455988/commenting-in-bash-script
Notepad++ -- Convert EOL from Windows to Unix after document has been created?: https://superuser.com/questions/1158769/notepad-convert-eol-from-windows-to-unix-after-document-has-been-created
DOS vs. Unix Line Endings: http://www.cs.toronto.edu/~krueger/csc209h/tut/line-endings.html

References

↑ 3 Terminal Commands to Increase Your Productivity: https://medium.com/better-programming/3-terminal-commands-to-increase-your-productivity-9dbab9f1a015
↑ Linux shell, how to use the exec option in find with examples: https://linuxaria.com/howto/linux-shell-how-to-use-the-exec-option-in-find-with-examples
↑ Guide to Nmap — Port Scanning is Just The Beginning: https://medium.com/@hakluke/haklukes-guide-to-nmap-port-scanning-is-just-the-beginning-25d971692fdb
↑ Nmap Network Scanning -- Port Scanning Techniques, Chapter 15 - Nmap Reference Guide: https://nmap.org/book/man-port-scanning-techniques.html
↑ Stream Editor - Quick Guide: https://www.tutorialspoint.com/sed/sed_quick_guide.htm
↑ Sed - An Introduction and Tutorial by Bruce Barnett: http://www.grymoire.com/Unix/Sed.html
↑ Linux SED command help: https://www.computerhope.com/unix/used.htm
↑ Example Uses of Sed in Linux: https://www.lifewire.com/example-uses-of-sed-2201058
↑ Learning Linux Commands -- sed: https://linuxconfig.org/learning-linux-commands-sed
↑ What is the difference between p and P in sed?: https://stackoverflow.com/questions/20194488/what-is-the-difference-between-p-and-p-in-sed
↑ How do you “debug” a regular expression with sed?: https://stackoverflow.com/questions/4052253/how-do-you-debug-a-regular-expression-with-sed
↑ How to extract text from a string using sed?: https://stackoverflow.com/questions/11568859/how-to-extract-text-from-a-string-using-sed
↑ Extract substring in Bash: https://stackoverflow.com/questions/428109/extract-substring-in-bash
↑ vi Editor “Cheat Sheet”: http://www.atmos.albany.edu/daes/atmclasses/atm350/vi_cheat_sheet.pdf
↑ Vi Cheat Sheet / Linux Terminal Cheat Sheet (PDF): http://www.smashingmagazine.com/2010/05/vi-editor-linux-terminal-cheat-sheet-pdf/
↑ How to copy paste contents in VI editor?: https://askubuntu.com/questions/256782/how-to-copy-paste-contents-in-vi-editor
↑ Why every software engineer should use vim: https://levelup.gitconnected.com/why-every-software-engineer-should-use-vim-b9fb97e69d97
↑ Wikipedia: Pico (text editor)
↑ Upgrading and installing packages through the Cygwin command-line?: https://superuser.com/questions/40545/upgrading-and-installing-packages-through-the-cygwin-command-line/301026#301026
↑ https://askubuntu.com/questions/645027/running-a-script-created-in-notepad-windows-on-ubuntu
↑ PDF export of TL;DR pages for Unix/Linux: https://tldr.sh/assets/tldr-book.pdf
↑ dos2unix MAN: http://linuxcommand.org/man_pages/dos2unix1.html