y.bat:

FOR /F %%I IN ('powershell Get-Date ^(Get-date^).AddDays^(-1^) -Format "yyyy-MM-dd"') DO SET yst=%%I%
echo Yesterday %yst%

>FOR /F %%I IN ('powershell Get-Date ^(Get-date^).AddDays^(-1^) -Format "yyyy-MM-dd"') DO SET yst=%%I%

>SET yst=2026-07-21

>echo Yesterday 2026-07-21
Yesterday 2026-07-21