Const InFolder = "ああ"
Const OutFileName = "ketugo.html"
Const ForReading = 1, ForWriting = 2
Dim fso, f, fc, fn, InFile, OutFile
Set fso = WScript.CreateObject("Scripting.FileSystemObject")
Set objWshShell = WScript.CreateObject("WScript.Shell")
Set RE = CreateObject("VBScript.RegExp")

RE.Pattern = InFolder & "*"
strPATH = Wscript.ScriptFullName
InFolder2 = Left(strPATH,InStrRev(strPATH,"\")-1)

Set f = fso.GetFolder(InFolder2)

Set fc = f.Files


Set OutFile = fso.OpenTextFile(OutFileName, ForWriting, true)
For Each fn in fc
If right(fn.name,5)=".html" and RE.Test(fn.name) and len(fn.name) = len(InFolder)+6 then
c= mid(fn.name,len(InFolder)+1,1)
if c>="0" and c<="9" then
Set InFile = fso.OpenTextFile(fn, ForReading)
OutFile.Write(InFile.ReadAll())
InFile.Close()
end if
end if
Next
OutFile.Close()
Set fso = Nothing
Set RE = Nothing

けっこう修正しないと ちゃんと動きませんでした｡

これまでにも利用してきたRegExpを使った例

Const InFolder = "ああ.html"
Const OutFileName = "ketugo.html"
Const ForReading = 1, ForWriting = 2
Dim fso, f, fc, fn, InFile, OutFile

Set fso = WScript.CreateObject("Scripting.FileSystemObject")
Set f = fso.GetFolder(InFolder)
Set fc = f.Files
Set OutFile = fso.OpenTextFile(OutFileName, ForWriting, true)

Set objEXP = New RegExp
objEXP.Pattern = "^ああ[0-9]\.html$"

For Each fn in fc
 If objEXP.Test(fn.Name) THEN
 Set InFile = fso.OpenTextFile(fn, ForReading)
 OutFile.Write(InFile.ReadAll())
 InFile.Close()
 End If
Next

元のｿｰｽに加えたのは下記2点です｡

' ﾊﾟﾀｰﾝ検索の準備
Set objEXP = New RegExp
objEXP.Pattern = "^ああ[0-9]\.html$"

' 下記の設定はﾃﾞﾌｫﾙﾄがFALSEなので今回は省きました｡
objEXP.Multiline = False
objEXP.Global = False

' ﾊﾟﾀｰﾝ適合性のﾃｽﾄ
 If objEXP.Test(fn.Name) THEN
 End If