Basic Commands

cd

• Usage
  • To change directories
• Examples

cd temp # browses to the directory called temp
cd /usr/bin # browses to /usr/bin folder
cd - # browse to previous directory
cd .. # browse to the parent direcotry
cd ../../ #browse 2 parent directories behind

pwd

• Usage

  • To print current working directory

• Examples

  pwd # simply lists the current folder you are in
  

ls

• Usage

  • To list all the files and directories

• Examples

  ls # lists current directory
  ls -l # list current directory with details
  ls -a # list all the hidden files
  ls -R # list recursively
  

  <p class="callout info">Please note, you can combine a number of the switches in one query rather than running them one by one. e.g. ls -lah</p>

mkdir

• Usage

  • to create a new directory

• Examples

  mkdir directory #create a folder with the name directory
  mkidr -p directory/data #create a folder with a subfolder called data
  

cp

• Usage

  • Copy a file from one place to another

• Examples

  cp hash /temp #copies file into the specified folder
  cp hash hash1 #copies the content of a file into a different one
  cp -r folder1/ folder2/ #copies the folder with it's content into a folder called folder2
  

mv

• Usage

  • To move a file from one place to another, also can be used to rename a file.

• Examples

  mv file1 ../ #moves the file from the current folder to the parent folder
  mv file1 file2 #renames file1 to file2
  

touch

• Usage

  • To create an empty file.

• Examples

  touch file1 #create file 1
  touch hash && echo "some_text" > hash # create a file cat hash and write in the file the words "some_text"
  

cat/tac

• Usage

  • To read the content of a file.

• Examples

  cat hash # read the content of the file called hash
  tac hash # same as above
  

rm

• Usage

  To remove a file or folder.

• Examples

  rm file1 # remove file1
  rm -rf folder1 # recursively remove the content of folder1 and discard any files in use.
  

grep

• Usage

  Search for a line or specific text in a file.

• Examples

  grep "text" file_with_text.txt # Print all lines that have the word "text"
  grep -c "text" file_with_text.txt # Count the number of occurences of the word "text"
  grep -i "text" file_with_text #Print all lines that contain the case insensitive word "text"
  

  
  

  The grep function has a ton of use cases, it can do regex matches, show lines before or after specific text and a lot more. I would advise to read the manual pages for more use cases. See the below URL for more information on the command: GNU Grep 3.7

head

• Usage

  • Read the first n lines of a file.

• Examples

  head file.txt # Default behaviour is to output the first 10 lines of a file
  head -n 3 # Output the first 3 lines of a file

tail

• Usage

  • Read the last n lines of a file

• Examples

  tail file.txt # Default behaviour, output the last 10 lines of a file
  tail -n 3 # Output the last 3 lines of a file

chmod

• Usage

  • To change the permissions of a file or folder

• Examples

  chmod +x file1 # make a specific file executable
  chmod 754 file1 # grant the file read, write, execute to user, read and execute to group and read to other

echo

• Usage

  • To write something in the console or file.

• Examples

  echo "Some really interesting text" #write the test between brackets

clear

• Usage

  • To clear the terminal windows of text.

• Examples

  clear # clears the terminal window

sudo

• Usage

  • To escalate your privileges to super user.

• Examples

  sudo ./script.sh # execute the script as root
  sudo apt install memes # escalate your privileges to install the application called memes