The example commands below are an 'Introductory Course' to working on command line. Please, scroll down for macOS / Linux Terminal commands.

Some Windows Command Prompt Commands

Command	Explanation
Although the example commands below are written with uppercase letters, you can also write them with lowercase letters.
D:	Select drive D.
CD \	Change to the root directory in the current drive.
CD ..	Change to the parent directory of the current directory.
CD myfiles	Change to the subdirectory (subfolder) named myfiles.
COPY testfiles1\somefile.txt	Copy file somefile.txt from the subdirectory named testfiles1 to the current directory.
COPY \testfiles1\somefile.txt	Copy file somefile.txt from the directory named testfiles1 to the current directory. testfiles1 is now a directory in the root of the current drive.
COPY \testfiles1\*.txt	Copy all files which have the name extension .txt from the directory testfiles1 to the current directory.
COPY goodtext.txt bettertext.txt	Copy a file named goodtext.txt to file named bettertext.txt in the current directory.
DEL useless.tmp	Delete the file named useless.tmp in the current directory.
DIR	Display a list of all files and subdirectories in the current directory.
DIR *.txt	Display a list of files that have the file name extension .txt in the current directory.
DIR s*	Display a list of files whose name begins with letter s in the current directory.
DIR *sum*	Display a list of files that have the word sum in their name in the current directory.
MD newfiles	Create (make) a subdirectory named newfiles into the current directory.
REN test.txt test.old	Rename a file named test.txt to test.old in the current directory.
TYPE sometext.txt	Display the contents of the file named sometext.txt
HELP | MORE	Display a list of all Command Prompt commands. When | MORE is added to the command, the list is shown one page at a time and with the Space key you get the next page.
HELP dir	Display information of the DIR command.
TAB key	With the tabulation key you can reduce typing. For example, if you first type letter S and then hit the TAB key, the system shows a file name if the current directory contains a file whose name starts with letter S.
Arrow Up / Arrow Down keys	With these keys you can scroll commands that have been given earlier in the Command Prompt window. For example, if you compile and run programs in the Command Prompt window, you do not always need to retype the necessary commands.

Some macOS / UNIX / Linux Terminal Commands

Command	Explanation
On macOS / UNIX / Linux uppercase and lowercase letters are not interchangeable in file names.
cd ..	Change to the parent directory of the current directory.
cd myfiles	Change to the subdirectory (subfolder) named myfiles.
cd ~	Change to the home directory of current user.
cp testfiles1/somefile.txt .	Copy file somefile.txt from the subdirectory named testfiles1 to the current directory using the same file name. The dot/full stop . is very important.
cp ~/Downloads/somefile.txt .	Copy file somefile.txt from the directory named Downloads to the current directory. Downloads is now a subdirectory in the home directory of the user. The dot/full stop . is very important.
cp goodtext.txt bettertext.txt	Copy a file named goodtext.txt to file named bettertext.txt in the current directory.
rm useless.tmp	Delete (remove) the file named useless.tmp in the current directory.
ls	Display a list of all files and subdirectories in the current directory.
ls -l	Display a list of all files with more information.
ls *.txt	Display a list of files that have the file name extension .txt in the current directory.
ls E*	Display a list of files whose name begins with uppercase E in the current directory.
ls *sum*	Display a list of files that have the word sum in their name in the current directory.
mkdir newfiles	Create (make) a subdirectory named newfiles into the current directory.
mv test.txt test.old	Rename a file named test.txt to test.old in the current directory.
cat sometext.txt	Display the contents of the file named sometext.txt
man cat	Display manual pages of the cat command. You can advance to the next page with the Space key, and quit with the Q key.
TAB key	With the tabulation key you can reduce typing. For example, if you first type letter S and then hit the TAB key, the system shows a file name if the current directory contains a file whose name starts with uppercase S.
Arrow Up / Arrow Down keys	With these keys you can scroll commands that have been given earlier in the Terminal window. For example, if you compile and run programs in Terminal window, you do not always need to retype the necessary commands.