Linux Command Cheat Sheet¶
Beginner Linux Command Line¶
This reference page contains a short list of commonly used Linux commands to help you get up and running with Linux in the Cyber Range.
Changes the current working directory
Changes to the previous directory
Changes to the $HOME directory
Changes to the parent directory
Prints the current working directory
Will list files in the current directory or a specified directory - Example: ls /home/user
Will list files in "long" format and show hidden files
Will list files in long format, by age, and in reverse
Allows a user to read the user manual for a specific command
Allows a user to create a directory - Example: mkdir myNewDirectory
mkdir -p 1/2
Make directory 1 along with subdirectory 2
Will remove the empty directory dir1
Will remove a specified file
Will remove all files starting with "file"
rm -r oldir
Will Recursively remove oldir & and all folder contents
Creates an empty file called "fileX", or will update the time of an existing file
cat f1 f2
Concatenate and print files f1 & f2
Nano editor, create or edit file1 (easy, simple)
Vim editor, create or edit file1 (difficult, powerful)
Leafpad graphical file editor (in XCFE, easiest)
Default graphic viewer in XFCE
Web/file downloader (www= a full URL)
curl -L www.ex.com/script1.sh | bash -c
Download & run a www hosted script locally
grep XX [file]
Filter & print any lines in file with XX in it
Filter & print any lines ^(beginning with) "Nmap"
somecommand | mail -s "Subject" firstname.lastname@example.org
Send output from somecommand to email in order to send an email to email@example.com
Print the time/date
Prints formatted YY-mm-dd date
Run embedded command and return text
cat /etc/passwd | cut -f1 -d":" | mail -s "Usernames on $HOST" firstname.lastname@example.org
Prints out all usernames on a system, cut the 1st column, and email it to me.
sudo su -
Super User Do, run the "su -" command to become root (if allowed)
ps auxw | less
List all processes, their PID #s, stats and process names (with less pager)
pstree | less
List all processes in a relational tree format (with less pager)
Networking & Network Security Commands¶
Please run any potentially dangerous system/network security commands in a safe environment (like the Cyber Range) or on a system where you have permission to do so!
Show IP and VLSM(255) subnet mask
ip addr show eth0
Show IP and CIDR(/24) subnet mask - The number of IPs on your LAN = 2^(32 - CIDR#) e.g. 2^(32-24) = 256 IPs.
Show the machine's (f)ull hostname
Show (I)P address of the hostname
ping -c 3 126.96.36.199
Ping Google's nameserver (188.8.131.52) three times
*Show (a)ll local to remote (T)CP IP/port connections & (p)rocess names
iptables -L -n
*(L)ist of firewall settings (n)umerically
Show IP routing tables (n)umerically
nmap -sP [IP/N]
**Ping scan the [IP/subnet address space of hosts]
nmap -sP -nS -oG..
**Ping scan (provide IP OR Network) and output in greppable format
nmap -oG - ..|
**Same, but pipe scan stdOut [-] to other command(s) (like grep)
nmap -O -n - [IP/N]
**Nmap OS fingerprint scan with no DNS
nmap -O --osscan-limit [IP/N]
**Limit OS port scan to promising targets
nc -lnk [IP#] [port#]
Have netcat listen locally on [your IP#] and [port#] * root needed for ports under 1024
echo "can you hear me?" | nc [remote IP] [remote Port]
Send a message to a remote process/listener on remote IP on a remote port number
#nikto -h www.example.com - Removing the # will allow the command to run
Scan webserver for known vulnerabilities. This command must be run as root, or via sudo command. WARNING! Do not run this without the target-host or network owner's permission.
Have a Question? Contact Support¶
Students: Please reach out to your Instructor or Admin who can submit a ticket to our Support team on your behalf.
If you are an Instructor or Admin and still have questions after reviewing the information above, please feel free to submit a ticket with our support team and we'll get back to you as soon as possible.
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