Nan Xiao's Blog

A system software / performance engineer's home

Month: July 2015

How to modify the local version of Linux kernel?

Execute “make menuconfig” command, then select “General setup” -> “Local version - append to kernel release“. Add you preferred name, e.g.: “.nan“, then save it.

Check if it is saved in .config file successfully:

[root@linux]# grep -i ".nan" .config
CONFIG_LOCALVERSION=".nan"

After making sure it is saved successfully, you can execute “make” command.

How to decompress “*.tar.xz” file?

Using “tar -Jxvf *.tar.xz” command can decompress “*.tar.xz” file. E.g.:

[root@localhost ~]# wget https://www.kernel.org/pub/linux/kernel/v4.x/testing/linux-4.2-rc3.tar.xz
[root@localhost ~]# tar -Jxvf linux-4.2-rc3.tar.xz

Fix “unsupported protocol scheme” issue in golang

When using “http” package in golang, you should use the full domain name, For example:

package main
import (
    "net/http"
    "fmt"
    "io/ioutil"
    "os"
)

func main() {
    resp, err := http.Get("www.google.com")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    text, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    fmt.Println(string(text))
}

Executing it, the error will be:

Get www.google.com: unsupported protocol scheme ""

Add “http://” before “www.google.com“, then executing it. The result is OK:

<!doctype html><html itemscope="" itemtype="http://schema.org/WebPage" lang="en"><head><meta co....

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