CrLf

还看到一个精巧的 awk 方案，小改如下：

gawk -F"_" "NR==FNR{a[$1]++}NR>FNR&&a[$1]>1" a.t
xt a.txt
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CrLf

也可以这样：

@echo off
(sort | uniq -w 7 -D)<a.txt
pause
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apang

来个vbs，闲的。

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

Do until file.AtEndOfStream
    str = file.ReadLine
    a = Left(str,InStr(str,"_"))
    If not dic.Exists(a) Then
        dic.Add a,str
    Else dic.Item(a) = dic.Item(a) & vbCrLf & str
    End If
Loop

For Each b in dic.Keys
    If InStr(dic.Item(b),vbCrLf) Then
        fso.OpenTextFile("b.txt",8,True).WriteLine dic.Item(b)
    End If
Next
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CrLf

一个方案：

@echo off&setlocal enabledelayedexpansion
for /f "delims=_" %%a in (a.txt) do set /a $%%a$+=1
for /f "delims=$" %%a in ('set $^|findstr /e "$=2"') do set "key=!key! %%a"
findstr /b "!key!" a.txt
pause
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