Terminal Commands

Basics

Working with Directories

• pwd Prints the working directory

• cd/path/to_directory Switches to the specified directory

• whoami Checks the current username

• ~ Swicthes to the home directory

• mkdirdir_name Creates a directory in the currect folder

  • -v flag that turns on “verbose” mode

• some_command--help Outputs a help menu of available commands along with their explanations Must come after a valid command

• ls List all of the files in the folder or directory

  • -l Formats the above command into a table

• rmdirdir_name Removes a directory

Working with Files

• touchfile_name.ext Creates a file in the current directory

• echo"Some text">file_name.ext Overwrites the quoted text into the file Note: Using >> appends to an existing file

• nanofile_name.ext Edits the file in a text editor

• statfile_name.ext Displays file stats and octal permissions

• chmod0--- file_name.ext Modifies file permissions. Each - is an octal number between 0-7 corresponding to a combination of read r, write w and execute x for each scope (owner, group, everyone).

• mvfile_name.ext dir_name Move the specified file into the specified directory Note: multiple files can also be specified between the command and destination

• cpfile_name01.ext file_name02.ext Create a copy of a file within the current directory

• rmfile_name.ext Remove the specified file from current directory

Working with Programs

• VAR="This is text" We can create Bash variables and assign values to them
  • Note: retrieving value of the variable is done by echo $VAR
• exportVAR="This is text" Creates an environment variable Accessing environment variables can also be done through Python.

  import os
  print(os.environ["VAR"])
  

Intermediate

Piping & Redirecting Output

• sort <file_name.ext The above command will sort the lines in an alphabetical order To reverse: sort-r< filename.ext

• grep"string" file_name.ext Will find and print out all lines in the file containing string

• grep "string" file_name?.ext Adding ? uses a wildcard character to fit similar file names An even broader wildcard character is *

• python file_name.py|grep "some_string" Piping operator | will chain commands together to redirect standard output to standard input

• catfilename.ext Concatenates the contents of the file

• echo "string" >> file_name.ext && cat fil_ename.ext Chaining several commands with && operator without passing ouput between them

• echo "\"" >> file_name.ext Escape character \ allows special characters to be treated as text

• head -n10 file_name.ext List first 10 lines from the file

• tail -n10 file_name.ext List last 10 lines from the file