How to get current datetime on Windows command line, in a suitable format for using in a filename?

Answer

See Windows Batch File (.bat) to get current date in MMDDYYYY format.:

@echo off
For /f \"tokens=2-4 delims=/ \" %%a in (\'date /t\') do (set mydate=%%c-%%a-%%b)
For /f \"tokens=1-2 delims=/:\" %%a in (\'time /t\') do (set mytime=%%a%%b)
echo %mydate%_%mytime%

If you prefer the time in 24hr/military format, you can replace the second FOR line with this:

For /f \"tokens=1-2 delims=/:\" %%a in (\"%TIME%\") do (set mytime=%%a%%b)

C:> .\\date.bat
2008-10-14_0642

If you want the date independently of the region day/month order, you can use \"WMIC os GET LocalDateTime\" as a source, since it\'s in ISO order:

@echo off
for /F \"usebackq tokens=1,2 delims==\" %%i in (`wmic os get LocalDateTime /VALUE 2^>NUL`) do if \'.%%i.\'==\'.LocalDateTime.\' set ldt=%%j
set ldt=%ldt:~0,4%-%ldt:~4,2%-%ldt:~6,2% %ldt:~8,2%:%ldt:~10,2%:%ldt:~12,6%
echo Local date is [%ldt%]

C:>test.cmd
Local date is [2012-06-19 10:23:47.048]