windows - How to check if a file exists from inside a batch file -

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i need run utility if file exists. how do in windows batch?

if exist <insert file name here> (     rem file exists ) else (     rem file doesn't exist )

or on single line (if single action needs occur):

if exist <insert file name here> <action>

for example, opens notepad on autoexec.bat, if file exists:

if exist c:\autoexec.bat notepad c:\autoexec.bat

shell