1. 读取文件
   1.1.数据准备
   
   1.2 代码准备

Sub test()
    Dim buf As String, n As Long
    Open "/Users/sixdog/Documents/VBA/test.txt" For Input As #1
        Do Until EOF(1)
            Line Input #1, buf
            n = n + 1
            Sheet1.Range("A" & n) = buf
        Loop
    Close #1
End Sub

1.3 执行结果确认

2.写入文件
2.1 准备空文件test2.txt

2.2 代码准备

Sub writeTest()

    Open "/Users/sixdog/Documents/VBA/test2.txt" For Append As #1
         For i = 1 To 10
            Print #1, "nihao" & i
         Next
    Close #1
 
End Sub

2.3 结果确认

3.数据覆盖写入
3.1 数据准备

3.2 代码准备

Sub writeTest()

    Open "/Users/sixdog/Documents/VBA/test4.txt" For Output As #1
         For i = 1 To 10
            Print #1, "你好" & i
         Next
    Close #1
 
End Sub

3.3 结果确认