Unix systems have a touch command that sets a file's last modification time to the current time. That's what this example does.

This program uses Command$ to look through its command line parameters. For each file listed, the program uses the SetFileTime API function to update the file's last modification time. That counts as a file access so it automatically updates the file's last access time. See the code for a LOT of details.

' Set the modification time for the files listed
' in the programs command line parameters.
Private Sub Main()
Dim commands As String
Dim file_name As String
Dim pos As Integer
Dim time_now As Date

    time_now = Now

    ' Get the command line arguments.
    commands = Command$
    Do While Len(commands) > 0
        ' Get the next file's name.
        pos = InStr(commands, " ")
        If pos = 0 Then
            file_name = commands
            commands = ""
        Else
            file_name = Left$(commands, pos - 1)
            commands = Trim$(Mid$(commands, pos + 1))
        End If

        ' Update the file's last modification time. Note
        ' that
        ' setting the modification time counts as accessing
        ' the file so it also sets the last access time.
        If SetFileModifiedDate(file_name, time_now, True) _
            Then
            MsgBox "Error setting last modification time " & _
                "for " & _
                file_name
        End If
    Loop
End Sub

' Return True if there is an error.
Public Function SetFileModifiedDate(ByVal file_name As _
    String, ByVal modified_date As Date, ByVal local_times _
    As Boolean) As Boolean
Dim file_handle As Long
Dim modified_filetime As FILETIME
Dim file_time As FILETIME

    ' Assume something will fail.
    SetFileModifiedDate = True

    ' Convert the date into a FILETIME.
    modified_filetime = DateToFileTime(modified_date)

    ' Convert the file time into a system file time.
    If local_times Then
        LocalFileTimeToFileTime modified_filetime, file_time
        modified_filetime = file_time
    End If

    ' Open the file.
    file_handle = CreateFile(file_name, GENERIC_WRITE, _
        FILE_SHARE_READ Or FILE_SHARE_WRITE, _
        0&, OPEN_EXISTING, 0&, 0&)
    If file_handle = 0 Then Exit Function

    ' Set the time.
    If SetFileModifiedTime(file_handle, ByVal 0&, ByVal 0&, _
        modified_filetime) = 0 Then
        CloseHandle file_handle
        Exit Function
    End If

    ' Close the file.
    If CloseHandle(file_handle) = 0 Then Exit Function

    SetFileModifiedDate = False
End Function

• Drag and drop files onto the program's executable
• Run it at a DOS prompt, as in touch.exe file1 file2 file3
• Install the program in Windows Explorer's Send To menu and send files to it