## Wednesday, 27 January 2021

### Learning the basics of Command Prompt

This is a tutorial I found that I included in a lecture I did on the 8th of March, 2017 at the Department of Civil Engineering and Geomatics at Cyprus Unviersity of Technology. The idea was to introduce the students to the basics commands of Command Prompt before explaining to the how to use my open source software DASOS (http://miltomiltiadou.blogspot.com/2015/03/las13vis.html). By quickly reading thought it, I think it worth sharing on my blog. :)

## Introduction

This tutorial gives you an overview of the basic line commands that can be executed using the  Microsoft Windows Command Prompt. By following the procedures of this tutorial, you will learn how to:
1. Open Command Prompt on Windows
2. View the contents of a directory
3. Change directory
4. More useful commands
5. Executing multiple commands using .bat files

## 1.Opening the Command Prompt window

The Command Prompt is the command-line interpreter on Windows machines. For example, it allows you to execute line commands for opening or modifying files. For windows 7 and  lower, the Command Prompt is found by searching ”Command Prompt” on the Star Menu  Search bar (Figure 1a). For windows 10, you will find it by pressing right click on the start  icon (Figure 1b). Inside the black window that appears, we can write and execute commands. Figure 2 shows a Command Prompt window. The last line shows the path of the working  directory, which in this case is C:\Users\Milto. The follow sections give an overview of a few basic commands.

## 2. Viewing the contents of a directory - <dir>

In order to view the content of the working directory we use the command dir. The name of the command dir is derived from the word ”directory”. Type the following at the command prompt and press ”ENTER” from the keyboard (Please
note this in this tutorial the $: shows the start of a command and it should be ignored.):$: dir

Once the ”ENTER” is pressed, a list similar to the following appears:

This is the list of all the files and subfiles of the working directory. The <DIR> label indicates that the listed item is a directory itself. If the working directory is not a drive (e.g. C:\), the first two directories ("." and "..") are always listed. The "." directory is the current working directory (C:\Users\Milto) and the ".." is the directory of the folder that contains the working directory (C:\Users). When a directory contains many items, the tag /p is very useful. For example, type the
following command:

$: dir /p This will print a page of the directory list and the next page appears once ”ENTER” is pressed. ## 3 Changing directory - <cd> Moving from one directory to another is essential and the command cd (named after ”change directory”) is responsible for that. From the working directory (C:\Users\Milto), you can move to the subdirectory Documents by typing the following:$: cd Documents

Or you may include the entire path of a directory. For example:

$: cd C:\Users\Milto\Documents By the way, when typing in Command Prompt you may use the tab button to quickly fill the name’s of directories and files. Try typing:$: cd C:\Us

and then press tab. It will automatically be filled to cd C:\Users. If more than one options apply, we can looping through them by pressing the button tab multiple times. Additionally, it is essential to be able to move from a working directory backwards; to the folder containing that working directory. This is done by the following command:

$: cd .. As mentioned before, the directory ".." is the directory of the folder that contains the working directory. Therefore, by using the command cd following with ".." , we can move backwards one folder. Similarly, the following command does nothing because it brings you to the current directory, which is the "." :$: cd .

The final command related to changing directory for this tutorial is the following:

$: cd \ Type the above command in Command Prompt. This command brings you to the root directory, which should by C:\. Therefore the Command Prompt should now show: C:\> Please note that for the final command a baskshlash (\) is used and not a forward slash (/); ## 4.Quick Overview of some useful commands There are numerous commands that can be executed from Command Prompt. Here a number of them are listed. To create a folder, use the command md (make directory) as follow. Please replace the <folderName> with the name of the new folder to be created.$: md <folderName>

With the command rd (remove directory), an empty folder can be deleted:

$: rd <folderName> For non-empty folders the tag \s should be added at the end as follow:$: rd <folderName> \s

For renaming a file:

$: ren <oldName> <newName> For deleting a file:$: del <filename>

For copying a file:

$: copy <file> <destination> An example of this command is the following which copies the file.txt from the directory C:Users into the C:\HelloWords:$: copy c:\Users\file.txt c:\HelloWorld

Similarly the structure of the command that moves files is the following:

$: move <file> <destination> The parameter NUL represents emptiness/null. Here, there is a hack for quickly generating an empty text file using the copy command and NUL:$: copy NUL emptyFile.txt

## 5.Executing multiple commands using batch (.bat) files

A batch file is a script file in Microsoft Windows. It consists of a series of commands, which are stored in a plain text file (most commonly with extension .bat). These commands can be executed by the command-line interpreter (Command Prompt). Figure 3 shows an example of a batch file that uses commands explained in this tutorial. Each line that starts with :: is a comment and it is ignored at execution time. Comments also do not influence the interpretation

of the commands.

As mentioned before, batch files are plain text files and they can therefore been edited using a text editor. A good option for editing batch files is the gedit application, which colours the commands. If gedit is not available, then WordPad will also work fine, but preferably avoid using Notepad because usually it does not identify new lines and there is no indentation. To run a batch script file, just double click on the file and all the commands will be executed. Once the execution is done, the command prompt closes automatically. To avoid that you may include the pause command at the end of the file.