IF
Performs conditional processing in batch programs.
IF [NOT] ERRORLEVEL number command
IF [NOT] string1==string2 command
IF [NOT] EXIST filename command
IF [NOT] DEFINED variable command
NOT Specifies that Windows CE 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.
The DEFINED conditional works just like EXISTS except it takes
an environment variable name and returns true if the environment
variable is defined.