CODEWITHSUNDEEP
batch-fileecho
Steve Richter
Steve Richter

Reputation: 63

Echo command with parenthesis in batch file

What function does the open parenthesis serve in this command?

Why is there no closed parenthesis?

>> datatest.csv.TEMP echo(!modified!

Upvotes: 4

Views: 1765

Answers (1)

SomethingDark
SomethingDark

Reputation: 14330

This is the result of a discussion on DosTips about nine years ago.

Your code will redirect the value of !modified! to datatest.csv.TEMP or it will print a blank line in that file if the variable is empty. According to echo /?, the official way to display a blank line is to use echo.. However, if cmd.exe is somehow able to find an executable with no extension called echo (for example, a file in the same directory as the script), that file gets used instead of the regular echo command.

A few alternatives to echo. were considered, including echo\, echo:, echo/ and echo(. echo\ was ruled out in case of a situation where there was a folder called echo that contained a file with the same name as whatever was being echoed. echo/ was ruled out in situations where the string to be displayed started with a ?, because in the case the help was displayed. echo: was ruled out for extremely rare situations where string substitution was being utilized.

Ultimately, echo( was ended up with simply because nobody could find a situation where it didn't work. (Later on, there was some speculation that echo=, echo,, and echo; are all safe to use without weird side effects or edge cases. However, if you are trying to display the literal string /?, the help for echo will be displayed instead.)

The ) is not included because it will get displayed.

Upvotes: 8

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