"directory" = "folder"

mkdir abc         - MaKe DIRectory
                    create a directory called abc

pwd               - Print Which Directory
                    remind me which directory I'm working in

cd abc            - Change Directory
                    start working in the directory called abc

cat xyz           - type out the contents of the file called xyz

cp def ghi        - CoPy the file def, name the copy ghi

cp ../pqr ./stu   - copy pqr from the parent directory into the
                    current directory, naming the copy stu

cp ../a.cpp .     - copy a.cpp from the parent directory into
                    the current directory, copy is also named a.cpp

CC prog.cpp       - C++ Compiler (CAPITAL Cs)
                    compile prog.cpp. If no errors call the executable
                    file a.out

           If you get a lot of error messages, press ENTER enough times
           to make them scroll off the top of the screen before entering
           pico, and you'll be able to scroll back to see them all.

a.out             - run it

mv a.out prog     - MoVe
                    change the name of a.out to prog

prog              - run that

rm name           - ReMove (delete) the named file

control-C stops nearly any running program.

pine              - run the email program
     C        Compose (send) a message
        control-X to send it when you've finished typing it
        to attach a file, use the up key to put the cursor on the
        "Attachment:" line near the top, then type control-J
     I        Index: look at your in-box
     Q        Quit: exit from pine