Set fso = CreateObject("Scripting.FileSystemObject")
Set dic = CreateObject("Scripting.Dictionary")
Set file  = fso.OpenTextFile("a.txt")

Do Until file.AtEndOfStream
   strLine = file.ReadLine
   strKey = Left(strLine,11)
   If Not dic.Exists(strKey) Then
      dic.Add strKey,strLine
   Else
      dic.Item(strKey) = dic.Item(strKey) & vbLf & strLine
   End If
Loop

For Each a in dic.Keys
   If UBound(Split(dic.Item(a),vbLf)) = 0 Then
      str = str & dic.Item(a) & vbCrLf
   End If
Next

fso.CreateTextFile("b.txt",True).Write str
MsgBox "OK"
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@echo off
(for /f "delims= " %%a in (1.txt) do (
  if not defined %%~na (
    set ok=&set %%~na=a
    call :sc "%%~na" "ok"
    if not defined ok echo %%a
)))>2.txt
start 2.txt&exit /b
:sc
for /f "skip=1 delims=" %%a in ('findstr /b %1 1.txt 2^>nul') do set %~2=.
goto :eof
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@echo off
(for /f "delims= " %%a in (1.txt) do (
  if not defined %%~na (
    set _=&set %%~na=a 
    for /f "skip=1 delims=" %%a in ('findstr /b "%%~na" 1.txt 2^>nul') do set "_=_"
    if not defined _ echo %%a 
)))>2.txt
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:: 删除倒数三个字符前相同的行
<"%~f0" more +11>1.txt
@echo off
(for /f "delims=-" %%a in (1.txt) do (
  if not defined %%~na (
    set ok=&set %%~na=a 
    for /f "skip=1 delims=" %%a in ('findstr /b "%%~na" 1.txt 2^>nul') do set "ok=-"
    if not defined ok echo %%a
)))>2.txt
start 2.txt&exit /b
323.456.789.781.561
593.658.651.780.658

323.456.789.781.542
323.456.789.781.798
323.456.789.781.256
981.651.654.782.681
981.651.654.782.682
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@echo off&setlocal enabledelayedexpansion
(for /f "delims= " %%a in (1.txt) do (
  set ".=%%a"&set ".=!.:~,11!"
  if not defined !.! (
	set _=&set !.!=a 
	for /f "skip=1 delims=" %%a in ('findstr /b "!.!" 1.txt 2^>nul') do set "_=_"
	if not defined _ echo %%a 
)))>2.txt
start 2.txt
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@echo off
for /f "delims=" %%a in (1.txt) do (
    set /a n=0
    for /f "delims=" %%b in ('findstr /b "%%~na" 1.txt') do set /a n+=1
    set /a "1/(n-1)" 2>nul||echo,%%a
)
pause
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gawk "{t=substr($0,0,11);n[t]++;a[t]=$0} END{for(m in n) if (n[m]<=1) print a[m]}" a.txt 
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@echo off&setlocal enabledelayedexpansion
for /f "delims=" %%i in (a.txt) do (
    set str=%%i&set "str=!str:~,11!"
    if not defined #!str! (
       set/a"n+=1"
       set #!str!=#&set "$!n!=%%i"
    ) else set "#!str!=$"
)
for /l %%i in (1 1 !n!) do (
    set str=!$%%i!
    for %%j in ("!str:~,11!") do if !#%%~j!# ==## echo !$%%i!
)
pause
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@echo off&setlocal enabledelayedexpansion
for /f "delims=" %%i in (a.txt) do (
    set str=%%i&set "str=!str:~,11!"
    set /a "$!str:~,11!+=1"
)
for /f "delims=" %%i in (a.txt) do (
    set str=%%i
    for %%j in ("!str:~,11!") do if "!$%%~j!" == "1" echo %%i
)
pause
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(for /l %%a in (1000,1,9000) do echo 111.22.%%a.333)>1.txt
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:: 别忘了在代码开头加一句set t=%time%

call :time0 "%t%" "%time%" "ok"
echo.&echo 耗时: %ok%
pause&exit
:time0  以下为封装部分。
:: code 随风 @bbs.bathone.cn 2008-08-15
setlocal&set /a n=0
for /f "tokens=1-8 delims=.: " %%a in ("%~1:%~2") do (
   set /a n+=10%%a%%100*360000+10%%b%%100*6000+10%%c%%100*100+10%%d%%100
   set /a n-=10%%e%%100*360000+10%%f%%100*6000+10%%g%%100*100+10%%h%%100
)
set "n=%n:-=%"
set /a s=n/360000,n=n%%360000,f=n/6000,n=n%%6000,m=n/100,n=n%%100
set "ok=%s% 小时 %f% 分钟 %m% 秒 %n% 毫秒"
endlocal&set "%~3=%ok%"&goto :eof
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@echo off&setlocal enabledelayedexpansion
for /f "delims=" %%i in (a.txt) do (
    set str=%%i&set "str=!str:~,11!"
    set /a "$!str:~,11!+=1"
)
for /f "delims=" %%i in (a.txt) do (
    set str=%%i
    for %%j in ("!str:~,11!") do if "!$%%~j!" == "1" echo %%i
)
pause
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gawk "{t=substr($0,0,10);n[t]++;a[t]=$0} END{for(m in n) if (n[m]<=1) print a[m]}" a.txt
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@echo off&setlocal enabledelayedexpansion
for /f "tokens=1-3* delims=." %%i in (a.txt) do if defined $%%i.%%j.%%k (set $%%i.%%j.%%k=1) else set "$%%i.%%j.%%k=0"
(for /f "tokens=1-3* delims=." %%i in (a.txt) do if "!$%%i.%%j.%%k!" == "0" echo %%i.%%j.%%k.%%l)>b.txt
pause
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gawk -F. "{c[NR]=$1 FS $2 FS $3;n[c[NR]]++;a[c[NR]]=$0} END{for(i=1;i<=NR;i++) if (n[c[i]]==1) print a[c[i]]}" a.txt
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