How do I compare timestamps of files in a batch script?

seriously, you should start to learn something else. Its not a joke. DOS(cmd.exe) seriously lacks date manipulation capabilities and many more deficiencies. Here's the next better alternative natively provided besides DOS batch, vbscript

Set objFS = CreateObject("Scripting.FileSystemObject")
Set objArgs = WScript.Arguments
strFile1 = objArgs(0)
strFile2 = objArgs(1)
Set objFile1 = objFS.GetFile(strFile1)
Set objFile2 = objFS.GetFile(strFile2)
If objFile1.DateLastModified < objFile2.DateLastModified Then
    WScript.Echo "File1: "&strFile1&" is older than "&strFile2
Else
    WScript.Echo "File1: "&strFile1&" is newer than "&strFile2
End If 

run it on command line

C:\test>dir
 Volume in drive C has no label.
 Volume Serial Number is 08AC-4F03

 Directory of C:\test

11/06/2009  07:40 PM    <DIR>          .
11/06/2009  07:40 PM    <DIR>          ..
11/06/2009  06:26 PM               135 file
11/02/2009  04:31 PM             4,516 m.txt

C:\test>cscript /nologo test.vbs file m.txt
File1: file is newer than m.txt

Of course, in newer versions of windows, you may want to try out Powershell...

I would use xcopy for this:

xcopy /L /D /Y PATH_TO_FILE1 PATH_TO_FILE2|findstr /B /C:"1 " && echo FILE1 is newer!

Because the xcopy always returns true in this case you need to filter its output with the findstr command.

• The /L is for listing only, nothing is copied.
• The /D is doing the time comparision. Hint: By swapping File1 and File2 you can decide how to handle identical files.
• The /Y in only necessary to avoid an 'Overwrite existing' question.

That's all and it works with different paths.

You can find the newer of two files with one line of batch script. Just list the files in date order, oldest first, which means the last file listed must be the newer file. So if you save the file name each time, the last name put in your variable will be the newest file.

For, example:

SET FILE1=foo.txt
SET FILE2=bar.txt
FOR /F %%i IN ('DIR /B /O:D %FILE1% %FILE2%') DO SET NEWEST=%%i
ECHO %NEWEST% is (probably) newer.

This unfortunately doesn't cope with the date stamps being the same. So we just need to check if the files have the same date and time stamp first:

SET FILE1=foo.txt
SET FILE2=bar.txt

FOR %%i IN (%FILE1%) DO SET DATE1=%%~ti
FOR %%i IN (%FILE2%) DO SET DATE2=%%~ti
IF "%DATE1%"=="%DATE2%" ECHO Files have same age && GOTO END

FOR /F %%i IN ('DIR /B /O:D %FILE1% %FILE2%') DO SET NEWEST=%%i
ECHO Newer file is %NEWEST%

:END

Dave Webb's soution while a great one will of course only work on files in the same directory.

Here is a solution that will work on any two files.

First get the file time (see How to get file's last modified date on Windows command line?).

for %%a in (MyFile1.txt) do set File1Date=%%~ta
for %%a in (MyFile2.txt) do set File2Date=%%~ta 

However one has then to manually break the date and time into it's components since Cmd.exe will compare them as a sting thus 2 > 10 and 10:00AM > 2:00PM.

Compare first the years, then the months, then the day, then AM/PM, then the hour, and then the minute and second, (actually time consuming, but I don't have on the minute a better idea), see the final code at the end.

However this solution will not work if the files are in the same minute but different by the second.

If you are to this level of precision then get the filetime by using the "forfiles" command (see https://superuser.com/questions/91287/windows-7-file-properties-date-modified-how-do-you-show-seconds).

for /F "tokens=*" %%a in ('forfiles /m MyFile1.txt /c "cmd /c echo @fdate @ftime"') 
    do set File1Date=%%a
for /F "tokens=*" %%a in ('forfiles /m MyFile2.txt /c "cmd /c echo @fdate @ftime"') 
    do set File2Date=%%a    

Note that "ForFiles" has a limitation that it can't take a path with spaces, so if you have a path with spaces you will have to change to that directory first, see forfiles - spaces in folder path

Comparison Code

:compareFileTime
set "originalFileTime=%1"
set "secondFileTime=%2"

for /F "tokens=1,2,3 delims= " %%a in (%originalFileTime%) do ( 
    set "originalDatePart=%%a"  
    set "originalTimePart=%%b"  
    set "originalAmPmPart=%%c"  
)
for /F "tokens=1,2,3 delims= " %%a in (%secondFileTime%) do (
    set "secondDatePart=%%a"
    set "secondTimePart=%%b"
    set "secondAmPmPart=%%c"
)
for /F "tokens=1,2,3 delims=/" %%a in ("%originalDatePart%") do (
        set "originalMonthPart=%%a"
        set "originalMonthDayPart=%%b"
        set "originalYearPart=%%c"

        rem We need to ensure that the year is in a 4 digit format and if not we add 2000 to it
        rem Cmd considers "50" > "100" but 50 < 100, so don't surround it with qoutes
    if %%c LSS 100 set "originalYearPart=20%%c
)
for /F "tokens=1,2,3 delims=/" %%a in ("%secondDatePart%") do (
    set "secondMonthPart=%%a"
    set "secondMonthDayPart=%%b"
    set "secondYearPart=%%c"    

    rem We need to ensure that the year is in a 4 digit format and if not we add 2000 to it
    rem Cmd considers "50" > "100" but 50 < 100, so don't surround it with quotes
        if %%c LSS 100 set "secondYearPart=20%%c    
)

if %originalYearPart% GTR %secondYearPart% goto newer
if %originalYearPart% LSS %secondYearPart% goto older

rem We reach here only if the year is identical
rem Cmd considers "2" > "10" but 2 < 10, so don't surround it with quotes or you will have to set the width explicitly
if %originalMonthPart% GTR %secondMonthPart% goto newer
if %originalMonthPart% LSS %secondMonthPart% goto older

if %originalMonthDayPart% GTR %secondMonthDayPart% goto newer
if %originalMonthDayPart% LSS %secondMonthDayPart% goto older

rem We reach here only if it is the same date
if %originalAmPmPart% GTR %secondAmPmPart% goto newer
if %originalAmPmPart% LSS %secondAmPmPart% goto older

rem we reach here only if i=t is the same date, and also the same AM/PM
for /F "tokens=1 delims=:" %%a in ("%originalTimePart%") do set "originalHourPart=%%a"

for /F "tokens=1 delims=:" %%a in ("%secondTimePart%") do set "secondHourPart=%%a"

rem Cmd considers "2" > "10" but 2 < 10, so don't surround it with qoutes or you will have to set the width explicitly
if %originalHourPart% GTR %secondHourPart% goto newer
if %originalHourPart% LSS %secondHourPart% goto older

rem The minutes and seconds can be compared directly
if %originalTimePart% GTR %secondTimePart% goto newer
if %originalTimePart% LSS %secondTimePart% goto older
if %originalTimePart% EQU %secondTimePart% goto same

goto older
exit /b

:newer
echo "newer"
exit /b

:older
echo "older"
exit /b

:same
echo "same"
exit /b