Batch files have been around since the early Ms DOS days. They are text files that contain a list of command-line executables. They can be compared to UNIX shell scripting, but are much simpler. For a file to be recognized by command.com (Microsoft’s DOS shell) it needs to have a .bat extension.
- To print a message on the screen use the echo command. For example:
echo Hello, World!
- By default the commands in a batch file are displayed at the prompt before being executed. To prevent this from happening start every command with an At sign ‘@’ or enter the following command at the top of the file:
- To use arguments passed to the batch file use the Percent sign ‘%’ followed by the argument’s number, for example to use the second and fourth arguments with echo:
echo Second Arg: %2, Fourth Arg: %4
- To redirect the output to a new file use the Greater Than sign ‘>’. If the file exists it will be overwritten. Here is an example that will save the directory listing to a file called dirlist.txt
dir > dirlist.txt
- To append the redirected output to the end of an existing file use 2 Greater Than signs next to each other ‘>>’. The following example appends another directory listing to the file from the previous example:
dir >> dirlist.txt
- To display the contents of a text file use the type command. Here is an example that displays the contents of the dirlist.txt file:
- Conditional processing is done using the if else statement. Following is an example that checks if a file exists before displaying its contents:
if exist C:\dirlist.txt (
) else (
echo The file does not exist.