How can I read the last 2 lines of a file in batch script

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情话喂你
情话喂你 2021-01-18 22:40

I have a Java program that appends new builds information in the last two lines of a file. How can I read them in batch file?

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  •  挽巷
    挽巷 (楼主)
    2021-01-18 23:17

    This code segment do the trick...

    for /F "delims=" %%a in (someFile.txt) do (
       set "lastButOne=!lastLine!"
       set "lastLine=%%a"
    )
    echo %lastButOne%
    echo %lastLine%
    

    EDIT: Complete TAIL.BAT added

    This method may be modified in order to get a larger number of lines, that may be specified by a parameter. The file below is tail.bat:

    @echo off
    setlocal EnableDelayedExpansion
    
    rem Tail command in pure Batch: Tail.bat filename numOfLines
    rem Antonio Perez Ayala
    
    for /F "delims=" %%a in (%1) do (
       set /A i=%2, j=%2-1
       for /L %%j in (!j!,-1,1) do (
          set "lastLine[!i!]=!lastLine[%%j]!
          set /A i-=1
       )
       set "lastLine[1]=%%a"
    )
    for /L %%i in (%2,-1,1) do if defined lastLine[%%i] echo !lastLine[%%i]!
    

    2ND EDIT: New version of TAIL.BAT added

    The version below is more efficient:

    @echo off
    setlocal EnableDelayedExpansion
    
    rem Tail command in pure Batch, version 2: Tail.bat filename numOfLines
    rem Antonio Perez Ayala
    
    set /A firstTail=1, lastTail=0
    for /F "delims=" %%a in (%1) do (
       set /A lastTail+=1, lines=lastTail-firstTail+1
       set "lastLine[!lastTail!]=%%a"
       if !lines! gtr %2 (
          set "lastLine[!firstTail!]="
          set /A firstTail+=1
       )
    )
    for /L %%i in (%firstTail%,1,%lastTail%) do echo !lastLine[%%i]!
    

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