Navigate the Filesystem
pwd ~ view current directory
cd ~ move into a directory
ls ~ list what is in a directory
View Files and Folders
cat ~ see content of a file
-n ~ see content with line numbers
less ~ see content of a file in editor
open ~ open files in the directory
Create and Delete Files and Folders
Move and Copy Files and Folders
Find Files and Folders
Search for Text
grep ~ search for text
grep "text" folder/file.js ~ search for text in whatever file
--color ~ search but colorize what we're looking for
-n ~ include the line numbers
-e ~ search but use regex
man grep ~ see all flags available
Make HTTP Requests
Create and Run Scripts
.sh ~ file has to end with this
chmod x+u ./file.sh ~ make file executable
- The command stands for change mode, giving the user the executable permissions
$ ~ Accept arguments in your script. They will be passed in chronological order when running the script: ./file.sh argument1 argument2
$(<command>) ~ run commands inside the bash script
# ~ write comments in bash
Store and Use Values
var=value ~ set a variable's value for a session
echo $var ~ print the variable
unset var ~ unset the variable
export var ~ make the variable available to all child processes
Understand and Use Functions
Create and call a function in bash:
hi() {
echo "Hello world"
}
hi
Function with an argument passed:
hi() {
echo "$1 world"
}
hi "Hello"
Assign function's return statement to a variable:
hi() {
echo "$1 world"
}
hiResult=$(hi "Hello")
echo "the result from hi is $hiResult"
local ~ create local variables only available within the function
Understand Exit Statuses
Use Conditional Statements
if [[ $USER = 'naruto' ]]; then
echo "true"
else
echo "false"
fi
[[ $USER = 'naruto' ]] && echo "yes" || echo "no"
Create Aliases in .bash_profile
On Ubuntu, if you don't create the .bash_profile file, it will use the existing configuration file ~/.profile .
gitm="git add . && git commit -m 'commit'" ~ example of an alias
Create and Copy multiple files with Brace Expansions
Items in the list of brackets.
touch index.js{,.backup} ~ create two files, index.js and index.js.backup , first item in the list is empty
mkdir -p packages/{pkg1,pkg2,pkg3}/src ~ create multiple packages inside packages folder, each containing src folder
echo {1..10} , echo {a..z} ~ print out ranges
You can use it for other things like creating multiple files
History expansion
!! ~ run the previous command
Default arguments
dir=${1:-$PWD} ~ users would pass the directory as the first argument, but it defaults to the current directory
Bash Keyboard Shortcuts
Ctrl+A - go to the beginning of a line
Ctrl+E- go to the end of a line
Ctrl+K - clears line up to the cursor
Ctrl+W - delete last word
Ctrl+L - clear the screen (equivalent of the clear command)
Complicated Conditional Statements
Case statements, they can also be on multiple lines:
case "$1" in
firstValue) echo "firstValue matched";;
secondValue) echo "secondValue matched";;
thirdValue)
echo "thirdValue matched"
;;
esac
