Go Programming Tips: Deleting Contents from a File

The Go language provides two methods to clear file contents: use io.Seek and io.Truncate, or use ioutil.WriteFile. Method 1 involves moving the cursor to the end of the file and then truncating the file, and method 2 involves writing an empty byte array to the file. The practical case demonstrates how to use these two methods to clear content in Markdown files.

Go Programming Tips: Clearing the Contents of Files

The Go language provides a series of powerful functions that can be used to clean files The system performs various operations, including deleting the contents of files. This article will explore two methods of deleting file content and further illustrate their use through practical cases.

Method 1: Using io.Seek and io.Truncate

##io.Seek Functions allow moving the read/write cursor within a file, while the io.Truncate function truncates the size of the file to a given length. By moving the cursor to the end of the file and then truncating the file, you effectively delete everything in the file.

package main

import (
    "io"
    "os"
)

func main() {
    // 打开文件
    f, err := os.OpenFile("test.txt", os.O_RDWR, 0644)
    if err != nil {
        panic(err)
    }
    defer f.Close()

    // 将光标移动到文件末尾
    _, err = f.Seek(0, io.SeekEnd)
    if err != nil {
        panic(err)
    }

    // 截断文件
    err = f.Truncate(0)
    if err != nil {
        panic(err)
    }
}

Method 2: Using ioutil.WriteFile

ioutil.WriteFile function can be used to write a byte array file, overwriting the original content. By passing an empty byte array, all contents of the file are cleared.

package main

import (
    "io/ioutil"
)

func main() {
    // 将空字节数组写入文件
    err := ioutil.WriteFile("test.txt", []byte{}, 0644)
    if err != nil {
        panic(err)
    }
}

Practical case

Suppose we have a Markdown file

test.md that contains text, and we need to delete its content.

Usage method 1:

import (
    "fmt"
    "io"
    "os"
)

func main() {
    filePath := "test.md"

    // 打开文件
    f, err := os.OpenFile(filePath, os.O_RDWR, 0644)
    if err != nil {
        fmt.Println("Error opening file:", err)
        return
    }
    defer f.Close()

    // 将光标移动到文件末尾
    _, err = f.Seek(0, io.SeekEnd)
    if err != nil {
        fmt.Println("Error seeking to end of file:", err)
        return
    }

    // 截断文件
    err = f.Truncate(0)
    if err != nil {
        fmt.Println("Error truncating file:", err)
        return
    }

    fmt.Println("File cleared successfully")
}

Usage method 2:

import (
    "fmt"
    "io/ioutil"
)

func main() {
    filePath := "test.md"

    // 将空字节数组写入文件
    err := ioutil.WriteFile(filePath, []byte{}, 0644)
    if err != nil {
        fmt.Println("Error writing empty file:", err)
        return
    }

    fmt.Println("File cleared successfully")
}

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