Introduction-to-Using-the-Command-Line.md

@@ -8,7 +8,7 @@
     1. [Mac OS](#mac-os)
     1. [Linux](#linux)
     1. [Microsoft Windows](#microsoft-windows)
-1. [Accessing another system with the Command Line](#accessing-another-system-with-the-command-line)
+1. [The Command Line Prompt](#the-command-line-prompt)
 1. [Getting started with basic commands](#getting-started-with-basic-commands)
     1. [Moving files](#moving-files)
     1. [Copying files and folders](#copying-files-and-folders)
@@ -18,14 +18,16 @@
     1. [Changing the current working directory](#changing-the-current-working-directory)
     1. [Making a new folder](#making-a-new-folder)
     1. [Getting help for a command](#getting-help-for-a-command)
+    1. [Common Commands](#common-commands)
 1. [Running scripts](#running-scripts)
+1. [Accessing another system with the Command Line](#accessing-another-system-with-the-command-line)
 1. [Permissions and ownership](#permissions-and-ownership)
 
 ## What is the Command Line
 
 The command line or command-line interface, is a text-based application for
 viewing, handling, and manipulating files on your computer. Other names for
-the command line are: cmd, CLI, prompt, console or terminal.
+the command line are: cmd, CLI, prompt, shell prompt, console, or terminal.
 
 A command line interface (CLI) processes commands to a computer program in the
 form of lines of text. The program which handles the interface is called a command
@@ -326,30 +328,41 @@ Click on “Accessories” and you’ll find the Command Prompt shortcut.
 
 Right click on the shortcut and press “Run as Administrator”.
 
-## Accessing another system with the Command Line
+## The Command Line Prompt
+After opening a terminal window as described in the previous section,
+you should see a white or black window that is waiting for your commands.
+The window will display a character or string called the command line prompt,
+aka 'shell prompt', or 'prompt' for short. It prompts you to input something there.
 
-Often it is not possible or inconvenient to access another system directly.
-If remote access has been enabled, one method to do this is through the Secure
-Shell (SSH), which lets you securely control and modify remote systems over
-the network.
+If you're on a Mac or Linux, you probably see a $ as the prompt
 
-You can do this by typing in `ssh username@host_server`
-where username is the account name of your account on the remote system, and
-host_server is the remote host.
+On Windows, you probably see a > as the prompt
 
-If you have a password to access your account on the server, SSH will
-prompt you to enter that in.
+The command line prompt is often configured to display the username, system name,
+current working directory, or other useful information but will usually end with
+either a $ sign, > symbol, or the &hash; symbol when logged in as the root user.
+For example, my prompt right now on my Mac is:
 
-If it’s your first time accessing that particular system, your computer may also
-ask you if it can remember the authenticity key — type in ‘yes’ or the corresponding
-phrase so that your computer doesn’t ask you this every time.
+`doctorwhen@Ronnies-Mac-Pro:~/src/MirrorCommandLine$`
 
-After successfully logging in to the remote system via SSH, you are presented with
-a command line prompt and commands you type in the terminal window at that prompt
-will be interpreted as commands to execute on the remote system. Exit the SSH
-session by logging out, usually by typing the command `exit`. After exiting the
-SSH session, commands issued at the command line prompt in your terminal window
-will be interpreted as commands to execute on the local system.
+At the prompt you can type a command which will be interpreted by the shell your
+login session is configured to use. I use the Bash shell. There are many shells,
+each offering its own value and all with similar but slightly different syntax,
+built-ins, functions, and features.
+
+For example, to display your username, type the following command at the prompt
+followed by <Return>
+
+Mac OS or Linux:
+
+`$ whoami`
+
+Windows:
+
+`> whoami`
+
+The `whoami` command should return your username followed by another shell
+prompt waiting for input.
 
 ## Getting started with basic commands
 
@@ -469,6 +482,48 @@ Often commands will display their usage when invoked with the '-h' or '-u' or
 -help' or '--help' option. The exact option to use for help varies from command
 to command.
 
+### Common Commands
+Here is a summary of some useful commands:
+
+<table border="0">
+  <tr>
+    <th style="text-align: center">Command (Windows)</th>
+    <th style="text-align: center">Command (Mac OS / Linux)</th>
+    <th style="text-align: center">Description</th>
+    <th style="text-align: center">Example</th>
+  </tr>
+  <tr>
+    <td>exit</td><td>exit</td><td>close the window</td><td><strong>exit</strong></td>
+  </tr>
+  <tr>
+    <td>cd</td><td>cd</td><td>change directory</td><td><strong>cd test</strong></td>
+  </tr>
+  <tr>
+    <td>cd</td><td>pwd</td><td>show the current directory</td><td><strong>cd</strong> (Windows) or <strong>pwd</strong> (Mac OS / Linux)</td>
+  </tr>
+  <tr>
+    <td>dir</td><td>ls</td><td>list directories/files</td><td><strong>ls</strong></td>
+  </tr>
+  <tr>
+    <td>copy</td><td>cp</td><td>copy file</td><td><strong>cp test/test.txt stage/test.txt</strong></td>
+  </tr>
+  <tr>
+    <td>move</td><td>mv</td><td>move file</td><td><strong>mv test/test.txt stage/test.txt</strong></td>
+  </tr>
+  <tr>
+    <td>mkdir</td><td>mkdir</td><td>create a new directory</td><td><strong>mkdir test</strong></td>
+  </tr>
+  <tr>
+    <td>rmdir (or del)</td><td>rm</td><td>delete a file</td><td><strong>rm test/test.txt</strong></td>
+  </tr>
+  <tr>
+    <td>rmdir /S</td><td>rm -r</td><td>delete a directory</td><td><strong>rm -r test</strong></td>
+  </tr>
+  <tr>
+    <td>[CMD] /?</td><td>man [CMD]</td><td>get help for a command</td><td><strong>cd /?</strong> (Windows) or <strong>man cd</strong> (Mac OS / Linux)</td>
+  </tr>
+</table>
+
 ## Running scripts
 To run a Python script, e.g. to run the script example.py, execute the command:
 
@@ -490,6 +545,31 @@ it can be executed and interpreted by Bash with the command:
 
 `./example.sh`
 
+## Accessing another system with the Command Line
+
+Often it is not possible or inconvenient to access another system directly.
+If remote access has been enabled, one method to do this is through the Secure
+Shell (SSH), which lets you securely control and modify remote systems over
+the network.
+
+You can do this by typing in `ssh username@host_server`
+where username is the account name of your account on the remote system, and
+host_server is the remote host.
+
+If you have a password to access your account on the server, SSH will
+prompt you to enter that in.
+
+If it’s your first time accessing that particular system, your computer may also
+ask you if it can remember the authenticity key — type in ‘yes’ or the corresponding
+phrase so that your computer doesn’t ask you this every time.
+
+After successfully logging in to the remote system via SSH, you are presented with
+a command line prompt and commands you type in the terminal window at that prompt
+will be interpreted as commands to execute on the remote system. Exit the SSH
+session by logging out, usually by typing the command `exit`. After exiting the
+SSH session, commands issued at the command line prompt in your terminal window
+will be interpreted as commands to execute on the local system.
+
 ## Permissions and ownership
 In Unix and Linux systems there is are the concepts of 'permission' and 'ownership'.
 Every file and directory has a set of permissions and ownership associated with it.