Difference between revisions of "User:Cyrusty/Useful Commands"

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@reboot sudo macchanger -r enp4s0 # (or eth0) # changes to random mac address on each reboot
 
@reboot sudo macchanger -r enp4s0 # (or eth0) # changes to random mac address on each reboot
 
</source>
 
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<source lang="bash">
 
<source lang="bash">

Revision as of 22:46, 27 July 2019

Linux Commands

cd # Home directory or changes directory
cd .. # Up a directory and to up 2 directories ../.. and so on
cd - # Returns you to the previous directory you were in
cd / # Changes directory to root
cd /proc # Changes directory to your running processes
ls # Lists the files that are in a directory
ls –a # Shows all files/hidden files in a directory
ls –al # Shows all files/hidden files and time/write permissions in a directory
ls -alh # Shows same as above command but shows file sizes in a better readable format
ls -l # Shows the files and write permissions in the directory
ls / # Shows the contents of the root directory
cat <file name. extension> # Prints the contents of a file on the shell
mkdir <Directory Name> # Makes a directory
mkdir -p EXAMPLE/RIGHT/IN/HERE # Makes multiple folders in the directory created
mv /FILE/NAME/OR/DIR /TO/DIR/WANTED # Moves a file to a directory or renames a file
rm <FILE NAME> # Removes a file
rmdir <DIRECTORY> # Removes an empty directory
rm –r # Removes a directory and its contents
rm -rf # Force deletes everything
rm –rf / # Deletes everything under root directory
sudo # Runs command as sudo
sudo bash # Changes to root privellages
sudo su # Gives SUPERUSER privellages
sudo !! # This will redo the previous command but instead runs it as sudo
su # switch USER
adduser USERNAME # Create a USER
adduser USERNAME sudo # Adds USER to the sudo group
passwd # Reset password for current user
man <COMMAND> # Displays a manual for a specific command
man hier # Displays a description of the filesystem hierarchy
grep # searching, finding, filtering command
top # Shows running processes
htop # Shows more information than top and in more detail
sudo renice -10 PID # This will prioritize a process (-20 being highest priority and 19 being lowest priority)
ps -A # Shows all running processes
kill PID # Kills process under a certain PID
kill -9 PID # Force kills a process that wont kill normally
sudo killall NAME # Kill all processes under the NAME
sudo pkill -u USER # Kills all USER processes
head FILENAME # Prints the first 10 lines
tail FILENAME # Prints the last 10 lines
clear # Clears the screen
pwd # Print working directory
<file name. extension> # Makes a file in current directory ##unsure of this##
cal # Shows current calender date (also cal mm/yy)
whatis # Type a command after to see a brief description of what it does/is
who # Shows current users on the machine and when they logged in
w # Shows whos logged in, from where, how long and what they're doing
nano # Edit a text file
vi # Nano is better...
vim # Another editor... type vimtutor on commandline to learn more
sort # Sort lines of text files
wc # Wordcount a text file
rig # Random Identity Generator
apt-cache search # ??

Networking

ifconfig # Shows network info IP/MAC address
sudo netdiscover # Shows who's on the network and identifies the ip address of each connection
sudo lsof -i # Lists the open ports and the process that owns them (to see which process is bound to port use :PORTNUMBER)
sudo netstat # Seeing what might be exposed to the network
sudo netstat -tulpn # t=tcp, u=udp ports, l=listening ports, p=processes, n=numerical
sudo macchanger -s enp4s0/eth0/wps/ # To see mac addresses
sudo macchanger -r enp4s0 # Changes the current mac address to a new one
ssh -NCD 1080 user@ip # Proxy network traffic over port 1080 (edit below settings on firefox to port traffic correctly)

Manual Proxy Configuration

Socks Host: localhost

port: 1080


SSH

ssh-keygen -t rsa # creates a key in .ssh
sudo nano /etc/ssh/sshd_config # change ssh parameters (key logging/password authentication)
sudo service ssh restart # saves ssh modifications
ssh-copy-id USER@IP # saves the pub key to be known as an authenticated key
scp -r USER@IP /home/USER/FILE/FOLDER /home/user/localmachine # copy from server to localmachine
scp -r /home/USER/localmachine/file/folder USER@IP:/home/USER/VPS # copy files from localmachine to server
sudo hostname -b NEWHOSTNAME # Renames the host
sudo nano /etc/hosts # Set unique names for IP's (makes shelling in faster using a desired name) eg. 172.321.123.123<TAB>VPS1
sudo apt-get install openssh-server # allows access to ssh into the computer through a LAN

System Info

df # Displays mounted devices
dmidecode | less # Shows bios information
lscpu # Shows cpu/hardware information
lspci # List all PCI devices
lsusb # List all USB devices
lsblk # List all Hard disks, Cd drives etc
cat /proc/meminfo # Shows memory information
cat /proc/version # Shows current running kernal version


Shutdown/Reboot

shutdown -r +60 # restarts in 60mins
shutdown -h +60 # shutdown in 60mins
poweroff # shuts system down
reboot # restarts computer
init 6 # same as reboot


Account Management

useradd # Adds a user
useradd -m -d # Create a new user and makes a home directory for the user and define the home directory /home/DIR/FOR/USER
sudo adduser <username> sudo # adds user to sudo privileges
userdel # Deletes a user
usermod -L USER # Locks the user from logging in
usermod -U USER # Unlocks the user so they can log in again
tail /etc/shadow
tail /etc/passwd
tail /etc/group

Note users will have a "!" after their name if they are locked out of their account to check this type in the above shadow command

File Permissions

(R)ead=4

(W)rite=2

(X)ecute=1

d=directory

l=link

4+2+1 = (r+w+x) = 7

4+2 = (r+w) = 6

4+1 = (r+x) = 5

4 = (r) = 4

2+1 = (w+x) = 3

2 = (w) = 2

1 = (x) = 1

chmod xxx dir # Change all files in a single directories permissions
chmod -R xxx dir # Change all file/folders permissions recursively
chown owner:group DIRECTORYNAME # Changes the owner and group name of files


Mail

mail # Checks mail for current user
mail -s "SUBJECT" USER < /home/USER/test.text # sends a mail to the user with test.text as the body
mail -f USER # Checks mail for selected user
mail -f guest # checks guest messages


Piping & Redirection

cat /FILE/IN/A/DIRECTORY | less # Shows in a opened document view without clogging the terminal
cat /FILE/IN/A/DIRECTORY | espeak # Speaks the text document in linux voice


Git

git add . # add all files for committing
git commit -am "COMMIT MESSAGE" # commit the changes locally
git push origin master # push changes to the server
git remote remove origin # Removes origin master

System Commands & Services

sudo apt-get update && sudo apt-get install # Updates n upgrades system to latest
crontab -e # the crontab (short for "cron table") is a list of commands that are scheduled to run at regular time intervals on your computer system
sudo nano /etc/default/grub # change grub options (boot timer)
cpulimit -b -l <PERCENTAGE> -p <PID> # Install cpulimit and use this command to restrict the amount of resources a program will use

Crontab Script Commands

@reboot sudo macchanger -r enp4s0 # (or eth0) # changes to random mac address on each reboot
@reboot sleep 20 && sudo shutdown 60 # will wait 20mins then schedule a shutdown 60mins later (just put this down as a reminder for sleep in crontab)
*  *    * * *   python3 /home/USER/ddns.py DNS 67f0ce616739484f82ca3837f40b401f # This will run the ddns.py script every 1 minute to detect if the ip changes and will update the domain (so the domain always points to the current ip address of the lappie/pc (of the router actually).

^The ddns.py script can be found here

Handy things to remember

ln -s /PATH/TO/SOMETHING/REAL /usr/local/bin/NAMEWANTED # can use executable file with preferred bind name
CTRL r # to search for previously used COMMAND
CTRL p # shows previously used COMMAND
CTRL a # brings you to begin of line
CTRL e # brings to the end of line
tail -f FILENAME # this will follow the file while it's being edited
echo "some kind of text" > example.text # this will overwrite the .text file with the quoted line
echo "new line of text" >> example.text # this will write the quoted line on a new line
alias COMMANDNAME="DESIREDNAME" # this will temporarily save a command to the desired name
echo "alias COMMANDNAME=\"DESIREDNAME\";" >> ~/.bashrc # this will permanently save a desired command to the bash file
&& # chain commands together
convert example.png example.jpg book.pdf # Converting files to PDF

> means to overwrite
>> means to append


Examples of Things

ls -alh /home/user/some/random/place >> ANYNAME # cat ANYNAME to see it show the directory with info
grep WHATEVERSEARCHINGFOR ./* # Useful for findings things.. If successful this will print out what it finds in the shell


Random Password Generators

openssl rand -base64 32 # generates random 32 character password
</dev/urandom tr -dc 'A-Za-z0-9!"#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' | head -c 10 ; echo # Sauls random character/symbol generated password command