Date/Time Named Files in DOS Batch
Producing date/time named files for output from DOS Batch
Summary
Good for when you want the output from a .BAT command file to be written to a date/time stamped file.
My Problem
Today I wanted to schedule a job to run on a clients machine several times a day for a number of weeks. Each time it ran I wanted an output file to with a name a bit like this :
DIAG-20100604T120000.txt
I find writing output to files which have their date/time of creation embedded in their names to be so useful it’s something I’m willing to muck around a bit to achieve.
The job i was running was all wrapped up in a .BAT file – how difficult could it be to get a .BAT file to produce a formatted date/time ? Well the answer is sufficiently difficult I side-stepped the problem !
Locale Independent
When I started looking for others who’d formatted date/times in .BAT land I found plenty of that made assumptions about the date/time format present on the machine it was running on but I really dislike using code like that – I’ve been bitten by it too many times in the past .
In the end I decided the only (or at least the easiest) thing to do was to allow a .VBS file to do the actual date/time formatting and allow the .BAT to use that.
First take some VBS
I pulled together a script I called iso.vbs.
The key thing with the VBS is the way the formatted date/time gets used in the last line. We’re going to use that output when we write some .BAT.
function addLeadingZeroIfNess(strIn)
if len(strIn) < 2 then
strOut = "0" & strIn
else
strOut = strIn
end if
addLeadingZeroIfNess = strOut
end function
'++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
OurDate = Now()
Yr = DatePart("yyyy",OurDate)
Mth = addLeadingZeroIfNess(DatePart("m",OurDate))
Dy = addLeadingZeroIfNess(DatePart("d",OurDate))
Hr = addLeadingZeroIfNess(DatePart("h",OurDate))
Mn = addLeadingZeroIfNess(DatePart("n",OurDate))
Sec = addLeadingZeroIfNess(DatePart("s",OurDate))
ISO = Yr & Mth & Dy & "T" & Hr & Mn & Sec
wscript.echo ISO
Now Add a bit of .BAT
Then I wrote a short .BAT file, iso.bat, which invokes the iso.vbs shown above and then invokes the ‘real’ .BAT which is the one I actually wanted to run, diag.bat
@echo off
for /f "delims=" %%a in ('cscript //nologo iso.vbs') do (set ISODateTime=%%a)
call diag.bat > "DIAG-"%ISODateTime%".txt"
iso.bat uses the formatted date/time (eg “20100604T120000”) produced by iso.vbs above to assign to the variable %ISODateTime%. The variable is then available to form part of the file name used for the diag.bat output.
A Bit of Context
If the machine I was using had either PowerShell or Python installed Iwould have come at this from a different angle but … it didn’t !
Credit Where Credits Due
A posting by Tom Lavedas in the vistax64 forums put me on the right track for passing the values from VBS to BAT land – for which my thanks.