Удалить часть строки вначале и в конце, включая пробелы и спец. символы

@echo off
for %%f in (*.txt) do (
 for /f usebackq^ tokens^=6^ delims^=^" %%a in ("%%f") do (
  if not "%%a"=="" >>$ (<nul set /p="%%a"& echo:)
 )
 if exist $ >nul move $ "%%f"
)
pause

@@  IF EXIST "__%~N0.exe" ( "__%~N0.exe" %* ) & (EXIT /B ERRORLEVEL) 
@@  FOR /F %%X IN ('DIR /B /S %WINDIR%\Microsoft.NET\Framework\CSC.EXE') DO @@(SET COMPILER=%%X)
@@  IF NOT DEFINED COMPILER (ECHO No .NET specific compiler presents in your computer !!!) & ( ECHO Goodbye !!! ) & ( EXIT/B -1 )
@@  FINDSTR /B /VC:@@  "%~F0" > "%~N0.cs"
@@  %COMPILER%  /OUT:"__%~N0.exe" /TARGET:exe "%~N0.cs"
@@  IF EXIST "__%~N0.exe" (ECHO Executable file __%~N0.exe created !!! ) & (ECHO Run %~N0 again !!!)  
@@  EXIT/B ERRORLEVEL
 
using System;
using System.IO;
using System.Text.RegularExpressions;
 
class ZZ
{
static void Main( string[] args )
{
    string filename;
    if ( args.Length > 0 ) {
        filename = args[0];
    }
    else {
        Console.Write("Enter input file name: ");
        filename = Console.ReadLine();
    }
    try {
        foreach ( var line in File.ReadLines(filename))
        {
            Match m = Regex.Match(line, "src=\"(?<url>[^\"]+)");
            if (m.Success) 
                Console.WriteLine(m.Value);
        }
    } catch ( Exception e ) {
        Console.WriteLine( e.Message );
    }
}
}

@echo off
for /f "tokens=1,2 delims=:" %%a in ('findstr /n /rc:" features " "1.txt"') do (
    call :step_1 "%%a" "%%b"
)
pause
exit
:step_1
for %%a in (%~2) do (
    if not %%a==features (
        set /A count+=1
    ) else (
        set /A count+=1
        call :step_2 %1
    )
)
:step_2
set /A number_string=%1+1
sed -i "%~1s/old/new/%count%g" "1.txt"
sed -i "%number_string%,$ s/old/new/g" "1.txt"
exit /b

@echo off
for /f "tokens=1,2 delims=:" %%a in ('findstr /n /rc:" features " "1.txt"') do (
    call :step_1 "%%a" "%%b"
)
pause
exit
:step_1
for %%a in (%~2) do (
    if %%a==old (
        set /A count+=1
    )
    if %%a==features (
        set /A count+=1
        call :step_2 %1
        exit /b
    )
)
:step_2
set /A number_string=%1+1
sed -i "%~1s/old/new/%count%g" "1.txt"
sed -i "%number_string%,$ s/old/new/g" "1.txt"
exit /b