Get date from file name and check age - batch-file

Question

I will have a variable that will be equal to anything from 1-7, which will represent 1 day old and so on. I need to find a file that is the same age in days as that variable.
For example
set "age=4"
// code to find the file OR folder that is 4 days old
It's worth noting that I need to get the filename of this file

Answer 1

Here, try this:
#echo off
setlocal
set age=4
set /a maxage=age+1
:: For files that are %age% days old or older, set a variable
for /f "delims=" %%I in ('forfiles /d -%age%') do (
set "fileArr[%%~snxI]=%%~fI"
)
:: for files that are %age% + 1 days old or older, unset variable
for /f "delims=" %%I in ('forfiles /d -%maxage%') do (
set "fileArr[%%~snxI]="
)
:: Get values of all remaining fileArr variables
for /f "tokens=1,* delims==" %%I in ('set fileArr') do echo(%%J
As you can see from the comments, first the script gets all files %age% days old or older, and sets a variable. To make the variable name unique and to be able to index it later, the variable name contains the short filename, simulating an associative array. Next, it unsets those variables which are %age% + 1 days old or older, then outputs what's left.
No painful date math is needed. forfiles handles the computation. If you needed age-by-minutes computation, admittedly that gets a little more complicated; but forfiles handles math by day just fine.

Answer 2

I found a much easier soloution:
ROBOCOPY "D:\file-backups\%ThisUser_Username%\Server"^
"%ThisService_WorkingDirectory%#DayZ_Epoch_Server\Addons"^
"dayz_server_*.pbo"^
/minage:%ThisService_filerestoreage%^
/maxage:%ThisService_filerestoreage%

Answer 3

In batch, as soon as you get the date of modification which corresponds to the age, (thus %DATE% - %AGE%), you can use the ~t modifier in a parameter expansion to get the age of the file.
Note that if you have PowerShell on your system (and you really should because it's preinstalled since Win7, cf comments) you can use it to do the date calculation easily.
Hence, a script that does what you want (with the parameter being %age% which you can replace with a command-line parameter for example) :
set age=4
for /f "delims=|" %%i in ('powershell.exe -Command "Get-Date -Format dd/MM/yyyy -Date ([DateTime]::Today.AddDays(-%age%))"') do set age_date=%%i
echo Files modified %age% days ago (the %age_date%) are :
setlocal ENABLEDELAYEDEXPANSION
for /f "delims=|" %%f in ('dir /b') do (
set file_date=%%~tf
if "!file_date:~0,10!"=="%age_date%" (echo %%f)
)
For a pure-batch script to get the date to replace the powershell call (say for legacy versions), you could slightly modifiy the code from here : http://www.powercram.com/2010/07/get-yesterdays-date-in-ms-dos-batch.html , even though that would get very ugly.
In contrast, unix-like systems have a tool for this, see man find, which is more user-friendly.
find /path/to/parent/directory -daystart -atime $age
atime : File was last accessed n*24 hours ago
$age without leading + or - : find exactly age of $age*24 hours (as opposed to less or equal, or superior or equal)
daystart :
Measure times (for -amin, -atime, -cmin, -ctime, -mmin, and
-mtime) from the beginning of today rather than from 24 hours
ago
You can use mtime instead of atime for modified date instead of creation date.