Batch Script — Comments

It’s always a good practice to add comments or documentation for the scripts which are created. This is required for maintenance of the scripts to understand what the script actually does.

For example, consider the following piece of code which has no form of comments. If any average person who has not developed the following script tries to understand the script, it would take a lot of time for that person to understand what the script actually does.

Comments Using the Rem Statement

There are two ways to create comments in Batch Script; one is via the Rem command. Any text which follows the Rem statement will be treated as comments and will not be executed. Following is the general syntax of this statement.

Syntax

where ‘Remarks’ is the comments which needs to be added.

The following example shows a simple way the Rem command can be used.

Example

Output

The above command produces the following output. You will notice that the line with the Rem statement will not be executed.

Comments Using the :: Statement

The other way to create comments in Batch Script is via the :: command. Any text which follows the :: statement will be treated as comments and will not be executed. Following is the general syntax of this statement.

Syntax

where ‘Remarks’ is the comment which needs to be added.

The following example shows the usage of the «::» command.

Example

Output

The above command produces the following output. You will notice that the line with the :: statement will not be executed.

Note − If you have too many lines of Rem, it could slow down the code, because in the end each line of code in the batch file still needs to be executed.

Let’s look at the example of the large script we saw at the beginning of this topic and see how it looks when documentation is added to it.

You can now see that the code has become more understandable to users who have not developed the code and hence is more maintainable.

How to Write a CMD Script

Related

If you have every used the Command Line, or CMD, interface in Windows, you probably have some idea of the powerful things it can do. Creating your own CMD scripts, you can do even more, but faster.

A CMD script does the same thing as if you typed commands into the CMD window. If you want to do something on a regular basis, such as telling Windows to turn off your computer after an hour, you can write a script and then you can activate the script whenever you want to run it.

Understanding CMD and Written Commands

In the early days of personal computing almost everything was done by typing command_s into a command line interface. If you wanted to open a program, you had to type the name of the program into the command line. Today, you can simply click or touch an icon on your screen to perform most actions. But Windows still accepts type-written commands in the CMD utility. You can write commands_ to open programs, add or change account permissions, back up files or get information about your computer using the CMD window.

Understanding CMD Scripts

The Command Prompt utility in Windows can be opened at any time, simply by typing «cmd» in the Windows Start menu. Here, you can type all sorts of commands to open programs, change settings and make tweaks to how Windows and its programs perform. In Microsoft’s long history of operating systems, CMD i_s a relative newcomer. In MS-DOS, before Windows was released, when you wanted to run a script, you would save it as a .bat file. While you can still save files with that extension today, most people use the .cmd extension._

Using a Script CMD to Open Notepad

To create and save a CMD switch, it’s best to use a basic text editor. Using a word processor like Microsoft Word makes saving the file a hassle. Notepad is much easier to use. So to demonstrate how CMD works, let’s open use it to open Notepad.

1. Type CMD in the Windows Start menu and press Enter to open CMD.exe.
2. Change the directory from your current username folder to the base directory by typing «cd\» and pressing Enter. It should now read «C:\>» before the blinking cursor.
3. Type the following line and pressEnter:start «c:\windows\system32» notepad.exe

As soon as you press Enter, you will see Notepad open. The command you entered has told Windows to start the notepad.exe program, which is located in the system32 folder, which is inside the Windows folder, on the C: drive. CMD commands are not case-sensitive so you can use lowercase or uppercase letters interchangeably.

Creating Your First Script CMD File

Now that Notepad is open, create your first CMD script file by typing the same line you used in the CMD window into notepad: start «c:\windows\system32» notepad.exe

Save the batch file to your desktop by selecting «Save As» from the File menu. Name the file «firstscript.cmd» and click «Save.» Notepad script commands must be saved with the .cmd extension, rather than the default .txt extension.

Double-click the new CMD file on your desktop. You will see the CMD window open for a fraction of a second and then close as Notepad is launched.

This is hardly a useful script, since a desktop shortcut does the same thing. To create something more useful, let’s edit the file so that it creates a new text file on your desktop listing all of your programs.

Using Echo and Echo Off

While the CMD window wasn’t open long enough to see it, by default it will always display the text that was entered in the CMD file when it runs. For longer scripts, this can be a nuisance, so it’s generally good form to turn this off by using the Echo Off command in the first line of the CMD file. By itself, Echo Off disables the display of any text that follows it. To make the Echo Off command apply to itself, put an @ symbol in front of it. Thus, your two-line CMD script would be:

@echo off

start «c:\windows\system32» notepad.exe

Creating a Text File Script

This CMD script will list all the files you have in your Program Files folder and put that list in a new text file.

1. Open Notepad. Type «@echo off«in the first line and press Enter.
2. In the second line, type: dir «C:\Program Files» > list_of_files.txt
3. Select «Save As» from the File menu and save the file as «program-list-script.cmd.»
4. Double-click the new text file on your desktop to see the list of files and folders.

The text file will appear in the same folder where the script file itself is. So if the script file is on your desktop, the list-of-files.txt file will also appear on your desktop.

If you want to change the folder where the text file is placed, you can specify its own folder in the script. For example, if you want it to be placed in your Documents folder, use: dir «C:\Program Files» > C:\Users\David\Documents\list_of_files.txt

Creating a Systems Information Script

If you want to use a script to give you needed information, it’s not always necessary to produce a text document with a script. You can have the information posted directly in the CMD window.

The example script below will give you basic information about your computer, including the operating system and version number, the BIOS version, the total physical memory and your computer’s network address. To use the script, type or copy the lines below into a new Notepad file and save it with the .cmd file extension, such as «my_computer_info.cmd.»

In this example, ECHO OFF is used to prevent the CMD window from displaying the script.

The ECHO command is used to display specific text, as well as some equal signs (===) as lines to organize the information in sections.

To insert a comment for your own use — without it affecting the script or appearing in the CMD window — type two colons first. Anything in the same line following » :: « will be commented out from the script.

The PAUSE command directs the CMD program to stay open. Pressing any key on your keyboard will close the window.

@ECHO OFF

:: This CMD script provides you with your operating system, hardware and network information.

TITLE My System Info

ECHO Please wait. Gathering system information.

ECHO OPERATING SYSTEM

systeminfo | findstr /c:»OS Name»

systeminfo | findstr /c:»OS Version»

ECHO BIOS

systeminfo | findstr /c:»System Type»

ECHO MEMORY

systeminfo | findstr /c:»Total Physical Memory»

ECHO CPU

wmic cpu get name

ECHO NETWORK ADDRESS

ipconfig | findstr IPv4

ipconfig | findstr IPv6

PAUSE

Using Scripts to Shut Down Your Computer

Normally, when you shut down your computer, it happens instantaneously. Suppose, however, that you’re listening to an audiobook or watching a training video — and you know that you will fall asleep after an hour. You can use a CMD script to tell your computer to shut itself down, after a specified period of time, using the shutdown command.

When you use the shutdown command, you need to include two additional switches, or subcommands. The first tells the computer to either shutdown or restart. You can use either -s or — r. The second tells the computer how many seconds to wait before performing the command. For this you use -t, followed by the number of seconds.

To shutdown the computer in one second, use: shutdown -s -t 01

To restart the computer in eight seconds, use: shutdown -r -t 08

To shutdown the computer in two hours use: shutdown -s -t 7200

Backing Up Files With a CMD Script

If you find it tedious to back up your files to a second storage device, using a CMD script makes the process a breeze. For this, use the Robocopy command. For example, if you want to back up all of the files in your Documents folder onto a removable storage device, you can write the command in a CMD file and then — at the end of the day — simply double click the file to activate it.

The Robocopy command needs to know, first — which folder you want to copy and, second — where you want the copy placed. Both the source and destination need to be in quotation marks.

If you’re not certain what your drive letters are, open File Explorer and click on «My Computer.»

For example, if your User name is MyName, your Documents folder is in your C: drive and your Backup folder is in a removable storage D: drive, then the command would be:

robocopy D:\Users\MyName\Documents F:\Backup /XA:H /W:0 /R:1 > F:\Backup\backup.log

This example is a bit more complicated, since Robocopy offers you a lot of options.

D:\Users\MyName\Documents: the folder you want to back up.

F:\Backup: the location of your Backup folder.

/XA:H: ignores hidden files.

/W:0: waits zero seconds between retries, instead of the default 30 seconds.

/R:1: retry only once if the file is locked.

> F:\Backup\backup.log: create a backup log placed in the Backup folder.

Note that because this is a mirror backup, if you delete files from the source folder, they will be deleted from the Backup folder the next time you use the script. It would be a good idea to explore additional switches available for Robocopy, so that you ensure that you backup your files the way that works best for you.

How do I display a text file content in CMD?

I want to display the content of a text file in a CMD window. In addition, I want to see the new lines that added to file, like tail -f command in Unix.

12 Answers 12

You can use the more command. For example:

We can use the ‘type’ command to see file contents in cmd.

More information can be found HERE.

I don’t think there is a built-in function for that

This opens the files in the default text editor in windows.

This displays the file in the current window. Maybe this has params you can use.

There is a similar question here: CMD.EXE batch script to display last 10 lines from a txt file So there is a «more» command to display a file from the given line, or you can use the GNU Utilities for Win32 what bryanph suggested in his link.

You can use the ‘more’ command to see the content of the file:

Using a single PowerShell command to retrieve the file ending:

It applies to PowerShell 3.0 and newer.

Another option is to create a file called TAIL.CMD with this code:

To do this, you can use Microsoft’s more advanced command-line shell called «Windows PowerShell.» It should come standard on the latest versions of Windows, but you can download it from Microsoft if you don’t already have it installed.

To get the last five lines in the text file simply read the file using Get-Content , then have Select-Object pick out the last five items/lines for you:

If you want it to display the content of the file live, and update when the file is altered, just use this script:

That will repeat forever until you close the cmd window.

You can do that in some methods:

One is the type command: type filename Another is the more command: more filename With more you can also do that: type filename | more

The last option is using a for for /f «usebackq delims=» %%A in (filename) do (echo.%%A) This will go for each line and display it’s content. This is an equivalent of the type command, but it’s another method of reading the content.

If you are asking what to use, use the more command as it will make a pause.

There is no built in option available with Windows. To constantly monitor logs you can use this free application BareTailPro.

You can get the TAIL utility from the Windows Server 2003 Resource Kit Tools.

If you want to display for example all .config (or .ini ) file name and file content into one doc for user reference (and by this I mean user not knowing shell command i.e. 95% of them), you can try this :

• ForFiles : loop on a directory (and child, etc) each file meeting criteria
  • able to return the current file name being process (@file)
  • able to return the full path file being process (@path)
• Type : Output the file content