Performs conditional processing in batch programs. Also Conditional symboles IF [NOT] ERRORLEVEL number command IF [NOT] string1==string2 command IF [NOT] EXIST filename command NOT Specifies that Windows NT should carry out the command only if the condition is false. ERRORLEVEL number Specifies a true condition if the last program run returned an exit code equal to or greater than the number specified. command Specifies the command to carry out if the condition is met. string1==string2 Specifies a true condition if the specified text strings match. EXIST filename Specifies a true condition if the specified filename exists. If Command Extensions are enabled IF changes as follows: IF [/I] string1 compare-op string2 command IF CMDEXTVERSION number command IF DEFINED variable command where compare-op may be one of: EQU - equal NEQ - not equal LSS - less than LEQ - less than or equal GTR - greater than GEQ - greater than or equal and the /I switch, if specified, says to do case insensitive string compares. The /I switch can also be used on the string1==string2 form of IF. These comparisons are generic, in that if both string1 and string2 are both comprised of all numeric digits, then the strings are converted to numbers and a numeric comparison is performed. The CMDEXTVERSION conditional works just like ERRORLEVEL, except it is comparing against an internal version number associated with the Command Extensions. The first version is 1. It will be incremented by one when significant enhancements are added to the Command Extensions. CMDEXTVERSION conditional is never true when Command Extensions are disabled. The DEFINED conditional works just like EXISTS except it takes an environment variable name and returns true if the environment variable is defined. %ERRORLEVEL% will expand into a string representation of the current value of ERRORLEVEL, provided that there is not already an environment variable with the name ERRORLEVEL, in which case you will get its value instead. Using this and the above numerical comparision operators, you can do the following choice goto answer%ERRORLEVEL% :answer0 echo You typed Y for yes :answer1 echo You typed N for no you can also use the numerical comparisons above: IF %ERRORLEVEL% LEQ 1 goto okay As far as I can tell, the only way to reliably set ERRORLEVEL to 0 (clear it) is to use VERIFY > NUL ERRORLEVEL can be set to 1 with FIND > NUL %CMDCMDLINE% will expand into the original command line passed to CMD.EXE prior to any processing by CMD.EXE, provided that there is not already an environment variable with the name CMDCMDLINE, in which case you will get its value instead.
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