How can I get a file's ctime, atime, mtime and change them

Question

How can I get file's ctime, mtime, atime use Go and change them?

In Go 1.1.2, * os.Stat can only get mtime * os.Chtimes can change mtime and atime but not ctime.

Answer 1

Linux

ctime

ctime is the inode or file change time. The ctime gets updated when the file attributes are changed, like changing the owner, changing the permission or moving the file to an other filesystem but will also be updated when you modify a file.

The file ctime and atime are OS dependent. For Linux, ctime is set by Linux to the current timestamp when the inode or file is changed.

Here's an example, on Linux, of implicitly changing ctime by setting atime and mtime to their original values.

package main

import (
    "fmt"
    "os"
    "syscall"
    "time"
)

func statTimes(name string) (atime, mtime, ctime time.Time, err error) {
    fi, err := os.Stat(name)
    if err != nil {
        return
    }
    mtime = fi.ModTime()
    stat := fi.Sys().(*syscall.Stat_t)
    atime = time.Unix(int64(stat.Atim.Sec), int64(stat.Atim.Nsec))
    ctime = time.Unix(int64(stat.Ctim.Sec), int64(stat.Ctim.Nsec))
    return
}

func main() {
    name := "stat.file"
    atime, mtime, ctime, err := statTimes(name)
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Println(atime, mtime)
    fmt.Println(ctime)
    err = os.Chtimes(name, atime, mtime)
    if err != nil {
        fmt.Println(err)
        return
    }
    atime, mtime, ctime, err = statTimes(name)
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Println(atime, mtime)
    fmt.Println(ctime)
}

Output:

2014-01-02 02:21:26.262111165 -0500 EST 2014-01-02 02:18:13.253154086 -0500 EST
2014-01-02 02:21:25.666108207 -0500 EST
2014-01-02 02:21:26.262111165 -0500 EST 2014-01-02 02:18:13.253154086 -0500 EST
2014-01-02 02:21:43.814198198 -0500 EST