Difference between %variable% and !variable! in batch file

Question

I am writing a batch file where I need to output a string containing '!' to another file. But when I echo that string to another file, it removes "!" from the output.

Eg: Input:

set LINE=Hi this is! output echo !LINE!>>new_file.txt 

Output in new_file.txt is:

Hi this is output 

Also, if input is

set LINE=Hello!! this is output!! echo !LINE!>>new_file.txt 

Output in new_file.txt:

Hello 

Hence, it skips the ! (Exclamation mark) from the output to the new_file. If I use %LINE%, then it simply displays "echo is on" to the output file.

Please suggest a way to overcome this problem.

Answer 1

If you have delayed expansion enabled and want to output an exclamation mark, you need to escape it.

Escaping of exclamation marks needs none, one or two carets, depending on the placement.

@echo off REM No escaping required, if delayed expansion is disabled set test1=Test1!  setlocal EnableDelayedExpansion REM One caret required REM Delayed expansion uses carets independent of quotes to escape the exclamation mark set "test2=Test2^!"  REM Two carets required REM The first caret escapes the second caret in phase2 of the parser REM Later in the delayed expansion phase, the remaining caret escapes the exclamation mark set test3=Test3^^!   echo !test1! echo !test2! echo !test3! 

The difference between !var! and %var% in blocks is explained at DOS batch: Why are my set commands resulting in nothing getting stored?

An explanation of the batch parser can be found at How does the Windows Command Interpreter (CMD.EXE) parse scripts?

Answer 2

It seems you have called SETLOCAL EnableDelayedExpansion somewhere higher in the code. Take a look here to see what the effects from that are.