General Code

Navigation

pwd — show current directory
ls — list files
ls -la — list all files with details
cd foldername — go into a folder
cd .. — go back one level
cd ~ — go to home directory
cd a/b/c — string

Files & Folders

touch file.txt — create a file
mkdir foldername — create a folder
- rm -rf foldername — delete a folder
rm file.txt — delete a file
cp file.txt dest/ — copy a file
mv file.txt dest/ — move or rename a file
cat file.txt — print file contents
vim foldername — open vim editor
vim -0 file.txt file.txt — vertical split

Inside vim

:vsplit — split vertically
Ctrl+w = — equal split
Ctrl+w w — switch between splits
:w — save
:q — quit
:wq — save and quit
:q! — quit without saving
:start,end d — delete lines
javac *.java — compile all bottom-up javac —enable-preview —release 21 *.java
jshell file.java file.java — in dependency order

jshell

jshell          # start jshell
/exit           # quit
/open file.java # load a java file into jshell
Ctrl + D        # end jshell

Things to declare

private static final double EPSILON = 1E-15;

Questions

When to use private / final / static etc?