In a remote shell to Thor, execute the whoami command Most Unix/Linux "Commands" are actually programs. The main purpose of a shell is to start and interact with other programs. A shell is a program for interacting with other programs. Unix/Linux systems come with many different command line shells. Modern Windows commputers come with two different command line shells, cmd and Powershell, and at least one graphical shell You can find out where a program is stored in the file system using the which command Execute the which command with whoami as the argument: which whoami Try which wc Try which hostname Try which man Try which which Depending on the particular shell program you use, you'll either see the output "which: shell built-in command." without quotes or you'll see a file system path to a program named which. There are a few commands built into the shell itself. When you type a command, the shell searches in the file system for programs with the specified name. Finding programs is a role of the shell and the which command is a way to find out which program the shell will find when it searches. Unix/Linux and Windows shells are programming language interpreters. One reason so many different shells exist is that each shell interprets a slightly different programming language. Users select a preferred shell based largely on personal preferences about programming languages. Almost every command line shell treats everything you type as the text of a program. It doesn't matter that most of the programs you write in a shell are only one line long. That's part of the power of shells. Unix/Linux shells allow the use of variables and "if" statements, "while" loops, and much more. To see the value of a variable use the echo command. echo $0 You should see the following output: "-tcsh" without the quotes (unless you or someone else has changed your default shell on Thor) Alomost every Unix/Linux command line program accepts arguments provided on the command line. The shell variable, $1 stores the first argument, $2 stores the second argument, and so on up to the limit of arguments for the shell. The limit is typically very large $0 stores the zero-th command line argument, the name of the program itself. A Unix/Linux shell is just a program like any other. Telling a shell to echo $0 means "echo the name of the program that's running the shell itself You can execute a new shell. Type the command, bash Then, execute echo $0. You should see "bash" output without the quotes. Type the exit command to exit bash and return to tcsh Bash and tcsh are two of many available shells. Select all of the following statements that are true
