Windows batch script help for checking last line of the file

Question

I have a few hundred files,most of which contains 'exit' at the end(the end line).Not all of the files have this 'exit' at the end.How can I check the content of last line of the files and then remove it if it's 'exit'?

Answer 1

I have written a hybrid JScript/batch utility called REPL.BAT that makes this task extremely simple and it is very fast. The utility reads stdin, performs any regular expression search and replace, and writes the output to stout.

The utility is a script that works on any modern version of Windows, starting with XP, and does not require installation of any 3rd party tools.

The following batch script processes all files in a given path and deletes the last line of each file only if it is the word exit with no other characters. I use the I option to make the search case insensitive. The M option is also required to allow searches across multiple lines. The regex could easily be refined as needed. For example, you could also match and remove the last line if it contains EXIT with whitespace.

@echo off
for %%F in (\somePath\*) do (
  type "%%F"|repl "^exit\r?\n?(?!\S|\s)" "" im >"%%F.new"
  move /y "%%F.new" "%%F" >nul
)

The REPL.BAT file must either be in your current folder (the folder you are running from), or better yet, in one of your PATH folders.

Here is the REPL.BAT script. I have found it incredibly useful for such a small script. Complete documentation is embedded within the script.

@if (@X)==(@Y) @end /* Harmless hybrid line that begins a JScript comment

::************ Documentation ***********
:::
:::REPL  Search  Replace  [Options  [SourceVar]]
:::REPL  /?
:::
:::  Performs a global search and replace operation on each line of input from
:::  stdin and prints the result to stdout.
:::
:::  Each parameter may be optionally enclosed by double quotes. The double
:::  quotes are not considered part of the argument. The quotes are required
:::  if the parameter contains a batch token delimiter like space, tab, comma,
:::  semicolon. The quotes should also be used if the argument contains a
:::  batch special character like &, |, etc. so that the special character
:::  does not need to be escaped with ^.
:::
:::  If called with a single argument of /? then prints help documentation
:::  to stdout.
:::
:::  Search  - By default this is a case sensitive JScript (ECMA) regular
:::            expression expressed as a string.
:::
:::            JScript regex syntax documentation is available at
:::            http://msdn.microsoft.com/en-us/library/ae5bf541(v=vs.80).aspx
:::
:::  Replace - By default this is the string to be used as a replacement for
:::            each found search expression. Full support is provided for
:::            substituion patterns available to the JScript replace method.
:::            A $ literal can be escaped as $$. An empty replacement string
:::            must be represented as "".
:::
:::            Replace substitution pattern syntax is documented at
:::            http://msdn.microsoft.com/en-US/library/efy6s3e6(v=vs.80).aspx
:::
:::  Options - An optional string of characters used to alter the behavior
:::            of REPL. The option characters are case insensitive, and may
:::            appear in any order.
:::
:::            I - Makes the search case-insensitive.
:::
:::            L - The Search is treated as a string literal instead of a
:::                regular expression. Also, all $ found in Replace are
:::                treated as $ literals.
:::
:::            B - The Search must match the beginning of a line.
:::                Mostly used with literal searches.
:::
:::            E - The Search must match the end of a line.
:::                Mostly used with literal searches.
:::
:::            V - Search and Replace represent the name of environment
:::                variables that contain the respective values. An undefined
:::                variable is treated as an empty string.
:::
:::            M - Multi-line mode. The entire contents of stdin is read and
:::                processed in one pass instead of line by line. ^ anchors
:::                the beginning of a line and $ anchors the end of a line.
:::
:::            X - Enables extended substitution pattern syntax with support
:::                for the following escape sequences:
:::
:::                \\     -  Backslash
:::                \b     -  Backspace
:::                \f     -  Formfeed
:::                \n     -  Newline
:::                \r     -  Carriage Return
:::                \t     -  Horizontal Tab
:::                \v     -  Vertical Tab
:::                \xnn   -  Ascii (Latin 1) character expressed as 2 hex digits
:::                \unnnn -  Unicode character expressed as 4 hex digits
:::
:::                Escape sequences are supported even when the L option is used.
:::
:::            S - The source is read from an environment variable instead of
:::                from stdin. The name of the source environment variable is
:::                specified in the next argument after the option string.
:::

::************ Batch portion ***********
@echo off
if .%2 equ . (
  if "%~1" equ "/?" (
    findstr "^:::" "%~f0" | cscript //E:JScript //nologo "%~f0" "^:::" ""
    exit /b 0
  ) else (
    call :err "Insufficient arguments"
    exit /b 1
  )
)
echo(%~3|findstr /i "[^SMILEBVX]" >nul && (
  call :err "Invalid option(s)"
  exit /b 1
)
cscript //E:JScript //nologo "%~f0" %*
exit /b 0

:err
>&2 echo ERROR: %~1. Use REPL /? to get help.
exit /b

************* JScript portion **********/
var env=WScript.CreateObject("WScript.Shell").Environment("Process");
var args=WScript.Arguments;
var search=args.Item(0);
var replace=args.Item(1);
var options="g";
if (args.length>2) {
  options+=args.Item(2).toLowerCase();
}
var multi=(options.indexOf("m")>=0);
var srcVar=(options.indexOf("s")>=0);
if (srcVar) {
  options=options.replace(/s/g,"");
}
if (options.indexOf("v")>=0) {
  options=options.replace(/v/g,"");
  search=env(search);
  replace=env(replace);
}
if (options.indexOf("l")>=0) {
  options=options.replace(/l/g,"");
  search=search.replace(/([.^$*+?()[{\\|])/g,"\\$1");
  replace=replace.replace(/\$/g,"$$$$");
}
if (options.indexOf("b")>=0) {
  options=options.replace(/b/g,"");
  search="^"+search
}
if (options.indexOf("e")>=0) {
  options=options.replace(/e/g,"");
  search=search+"$"
}
if (options.indexOf("x")>=0) {
  options=options.replace(/x/g,"");
  replace=replace.replace(/\\\\/g,"\\B");
  replace=replace.replace(/\\b/g,"\b");
  replace=replace.replace(/\\f/g,"\f");
  replace=replace.replace(/\\n/g,"\n");
  replace=replace.replace(/\\r/g,"\r");
  replace=replace.replace(/\\t/g,"\t");
  replace=replace.replace(/\\v/g,"\v");
  replace=replace.replace(/\\x[0-9a-fA-F]{2}|\\u[0-9a-fA-F]{4}/g,
    function($0,$1,$2){
      return String.fromCharCode(parseInt("0x"+$0.substring(2)));
    }
  );
  replace=replace.replace(/\\B/g,"\\");
}
var search=new RegExp(search,options);

if (srcVar) {
  WScript.Stdout.Write(env(args.Item(3)).replace(search,replace));
} else {
  while (!WScript.StdIn.AtEndOfStream) {
    if (multi) {
      WScript.Stdout.Write(WScript.StdIn.ReadAll().replace(search,replace));
    } else {
      WScript.Stdout.WriteLine(WScript.StdIn.ReadLine().replace(search,replace));
    }
  }
}

Answer 2

   setlocal enabledelayedexpansion 
   for /f "delims=" %%Z in ('dir /s /b /a-d .') do (
       for /f "delims=" %%a in (%%Z) do  set last_line=%%a
       echo !last_line! | find "exit" && del /f /q %%Z
    )
    endlocal

edit (foxidrive reads more carefully than me):

  @echo off

  setlocal enabledelayedexpansion 
   for /f "delims=" %%Z in ('dir /s /b /a-d') do (

       set /a counter=1
       set "yes=no"
       for /f "usebackq delims=" %%a in ("%%Z") do  set last_line=%%a&& set /a counter=counter+1
       echo !last_line! | find /I "exit" >nul&& set "yes=yes"
       if "!yes!" equ "yes" (
          break >"%%Z.tmp"
          for /f "usebackq delims=" %%a in ("%%Z") do (
             set /a counter=counter-1
             if "!counter!" neq "1" (
                endlocal
                echo %%a | find "ECHO is off.">nul&&echo\>>"%%Z.tmp"   
                echo %%a | find "ECHO is off.">nul||echo %%a>>"%%Z.tmp"
            )
          )
          echo "Exit" found in  at the end of --%%Z--
          copy /y "%%Z.tmp" "%%Z" >nul 
       )
    )
    endlocal

edit:working and a little bit improved.Still does not manage with empty lines , but now it's better.

Answer 3

for sed "only":

for %i in (*) do @sed -i"%~i.bak" "$ {s/exit/exit/i;/exit/d}" "%~i"

Answer 4

Borrowing the code from @npocmaka and using GNUsed then this should be pretty robust and preserve blank lines and work with long filenames etc. It processes the entire directory tree. It's untested.

@echo off
setlocal enabledelayedexpansion 
for /f "delims=" %%Z in ('dir /s /b /a-d') do (
   for /f "delims=" %%a in ('type "%%Z"') do set "last_line=%%a"
     echo !last_line! | find /i "exit" >nul && (
        sed $d "%%Z" > "%%Z.tmp"
        move /y "%%Z.tmp" "%%Z" >nul
 )
)
endlocal

Answer 5

@echo off
setlocal EnableDelayedExpansion

rem "I have a few hundred files"
for %%a in (*.*) do (
   rem "most of which contains 'exit' at the end line."
   set "lastLine="
   (for /F "usebackq delims=" %%b in ("%%a") do (
      if not defined lastLine (
         set "lastLine=%%b"
      ) else (
         echo(!lastLine!
         set "lastLine=%%b"
      )
   )) > "%%~Na.tmp"
   rem "Not all of the files have this 'exit' at the end."
   rem "How can I check the content of last line of the files"
   if "!lastLine!" equ "exit" (
      rem "and then remove it if it's 'exit'?"
      move /Y "%%~Na.tmp" "%%a"
   ) else (
      del "%%~Na.tmp"
   )
)