Windows batch file if then

We've written in the past about how to use Windows scripts for processing data to an Excel file ; some good background reading. Using a batch file to check whether a file exists in a directory is quick and easy. Here's what that script looks like.

For example if you have a system or application running that creates new error logs in a specific folder when there's a problem, you can run a batch job every so often to monitor whether new error logs are created so you can send an alert. An aspect of batch file scripting that too few IT folks or programmers use is checking for errors. There are a lot of batch jobs floating around out there that are performing critical IT tasks like backing up important files or running file copy operations.

When these batch jobs fail, systems fail and people notice. It's much smarter to get an alert when your batch job has failed a command before people start noticing. This way you can fix the issue proactively. If the application or command returned a zero, all is fine. If not, then you need to send yourself an email.

You don't have to take the email route. You could always write an error log that you might check every morning, or launch a second application or command that attempts to do the copy using an alternate command.

If you'd rather use an IF statement to check for specific error codes, Windows offers a pretty extensive list of error codes. If the condition specified in an if clause is true, the command that follows the condition is carried out. If the condition is false, the command in the if clause is ignored and the command executes any command that is specified in the else clause.

When a program stops, it returns an exit code. To use exit codes as conditions, use the errorlevel parameter. You must use the else clause on the same line as the command after the if.

To display the message Cannot find data file if the file Product. To format a disk in drive A and display an error message if an error occurs during the formatting process, type the following lines in a batch file:.

Commands in batch programs also supports all the operators that other scripting languages support. It also serves to have a quick review at all the operators with their description.

Form your own expressions for every operator using some variables and evaluate the results. Assuming that now you are comfortable with operators and variables, we move on to the next topic. A computer program is defined to be a block of code that takes some inputs to the user, performs the computation and returns the result of computation to the user.

Conditional statements are very essential in any computer program. Conditional statements allow us to do different things in our program based on the conditions. Without these conditional statements, our code would do the same thing every time it is given an input. This is an important difference because if you compare numbers as strings it can lead to unexpected results: "2" will be greater than "19" and "" will be less than "10". IF should work within the full range of 32 bit signed integer numbers -2,,, through 2,,, You can perform a string comparison on very long numbers, but this will only work as expected when the numbers are exactly the same length:.

You see things; and you say 'Why?