CLI cheatsheet

• pwd: print working directory: prints the current folder you are in
• cd Downloads: goes into directory Downloads
• ls: lists all files and directories in the current working directory
• rm file: removes file
• mkdir a: makes a directory named a
• wget url: Downloads the file the URL points to
• cp file_a file_b: copies file_a into a new file file_b
• mv file_a file_b: moves file_a into file_b. Useful for renaming files.
• touch file_a: creates an empty file file_a
• nano file_a: opens file_a to edit in an interactive terminal-based editor.
• less file_a: lets you view a file on the command line.
• cat file_a file_b ...: prints the contents of all the files concatenated in order. Can also be used to view a single file.
• man cmd: instructions on how to use a certain command
• echo hi: prints hi
• Pipes: use the output of one command as input for another: fortune | cowsay
• Redirection: redirect the output of a command to a file: ls > files.txt

Bash scripting

You can combine sequences of commands together into one file to run all at once. Bash also contains some useful constructs to write more complicated programs.

• variables: NAME="chinmaya" DIR=$(pwd)

• if:

if [[ $(date +%H) -ge 11 ]]; then
  echo "it's past 11"
else
  echo "it's not past 11"
fi

• while:

while true; do
  echo hello
  sleep 2
done

• for:

for i in *; do
  cp $i new_folder/$i
done