There are basically two types of UNIX commands.
In one type you ask the computer for information.
For example, if you type
the computer will respond by printing a list of your files on the screen.
In the other type of command, you ask the computer to do something.
It doesn't necessarily need to print any response. These types
of commands usually are asking for something to be done to a file.
The basic form of these commands is command filename.
These tells the machine to perform the action dictated by command
on the file that is called filename. An example is:
which deletes the file named paper.tex from the system.
Many UNIX commands have options. These are preceded on the
command line by a minus sign -. The basic form is:
command -option filename, or just
command -option. Two examples are:
rm -i paper.tex