extracting a changing and unknown hashcode from text document in batch - batch-file

Question

i wanted to code a little update tool for a server.jar file to save me all the effort of doing it manually
the program i'm using creates a folder which contains a file when a new update is released. this is pretty much how the program works:
get hash of current server.jar
find latest created folder (eg. update12)
open the file in the update12 folder (eg. update12.txt)
***extract the hash code -> %newHash%*** thats where im having the issue
compare the extracted hashcode (%newHash%) and the calculated hashcode (%currentHash%)
if they are not equal go to www.downloadupdate.com/updates/%newHash%/server.jar
download the file and replace the old server.jar with the new one.
the issue i am having is that i cant read out the hash in the update12.txt the file is about 36000 symbols long and in one line only
"server": {"sha1": "16f18c21286a3f566d3d0431d13aa133bebe6eff"
i want to detect the "server": {"sha1": " part and copy the hash after that
i tried many options i found on this forum but none seemed to work
like this one
set /p txt=<update12.txt
pause >nul
echo %txt%
pause >nul
for /f %%i in ('powershell -noprofile -c "('%txt:"=\"%' -split '\""')[1]"') do set id=%%i
echo %id%
just caused the batch file to close instantly
furthermore set /p txt=
if you have any solution i would be grateful to hear it

Answer 1

#echo off
Setlocal EnableDelayedExpansion
xcopy %appdata%\.minecraft\versions\%MCversion%\%MCversion%.json %appdata%\.minecraft\versions\%MCversion%\%MCversion%.text*
ren %appdata%\.minecraft\versions\%MCversion%\%MCversion%.text %MCversion%.txt
set search1=
set search2=,
set search3=:
set textFile=%appdata%\.minecraft\versions\%MCversion%\%MCversion%.txt
:PowerShell
SET PSScript=%temp%\~tmpStrRplc.ps1
ECHO (Get-Content "%textFile%").replace("%search1%", "") ^| Set-Content "%textFile%">"%PSScript%"
Powershell -ExecutionPolicy Bypass -Command "& '%PSScript%'"
SET PSScript=%temp%\~tmpStrRplc.ps1
echo done.
ECHO (Get-Content "%textFile%").replace("%search2%", "") ^| Set-Content "%textFile%">"%PSScript%"
Powershell -ExecutionPolicy Bypass -Command "& '%PSScript%'"
SET PSScript=%temp%\~tmpStrRplc.ps1
echo done.
ECHO (Get-Content "%textFile%").replace("%search3%", "") ^| Set-Content "%textFile%">"%PSScript%"
Powershell -ExecutionPolicy Bypass -Command "& '%PSScript%'"
SET PSScript=%temp%\~tmpStrRplc.ps1
echo done.
:skip
ECHO (Get-Content "%textFile%").replace("server", "`r`nlookup") ^| Set-Content "%textFile%">"%PSScript%"
Powershell -ExecutionPolicy Bypass -Command "& '%PSScript%'"
echo done.
for /f %%a in ('findstr "lookup\"{\"sha1\"\"" %textFile%') do set "newVersion=%%a"
set newVersion=%newVersion:~15,40%
echo %newVersion%
del %textFile%
pause
:exit
exit
this code works for me, what it does:
copy the "update12.txt"
look for " " "," and ":" in the copied txt and delete the symbols
look for server replace it with a "*linebreak*lookup"
find the string lookup"{"sha1""
trim the edges of the string with 15,40
done.