Very powerful in that you can do a lot of different things in it. On Ruby, we use the T shell, which is an improved version of the C shell. The prompt may differ depending on the shell. Optional flags are one letter, follow a dash, and modify the way the command works. More than one flag can follow the dash.
Optional arguments are what the command acts upon.
Use the up and down arrows to recycle through commands you've entered before. The UNIX command, ls -l , will list the contents of the current directory in the long form. Then r , w , and x , indicate whether the file has read, write, or execute permissions. This will allow everyone to be able to read your file on the Web.