从来没有这么强烈想推荐一个工具

$ curl cheat.sh/tar
$ curl cht.sh/go
$ curl https://cheat.sh/php
$ curl https://cht.sh/redis

$ curl cht.sh/~snapshot

$ curl "http://cheat.sh/go/execute+external+program?Q"
cmd := exec.Command("yourcommand", "some", "args")
if err := cmd.Run(); err != nil {
    fmt.Println("Error: ", err)
}

mkdir -p ~/bin/
curl https://cht.sh/:cht.sh > ~/bin/cht.sh
chmod +x ~/bin/cht.sh

$ cht.sh go execute external program

$ cht.sh --shell [LANG]

cht.sh> help
help    - show this help
hush    - do not show the 'help' string at start anymore
cd LANG - change the language context
copy    - copy the last answer in the clipboard (aliases: yank, y, c)
ccopy   - copy the last answer w/o comments (cut comments; aliases: cc, Y, C)
exit    - exit the cheat shell (aliases: quit, ^D)
id [ID] - set/show an unique session id ("reset" to reset, "remove" to remove)
stealth - stealth mode (automatic queries for selected text)
update  - self update (only if the scriptfile is writeable)
version - show current cht.sh version
/:help  - service help
QUERY   - space separated query staring (examples are below)
              cht.sh> python zip list
              cht.sh/python> zip list
              cht.sh/go> /python zip list

i   case insensitive search
b   word boundaries
r   recursive search

cht.sh>/go md5

/*
 * cryptography - How to get a MD5 hash from a string in Golang ...
 *
 * From crypto/md5 doc (http:golang.org/pkg/crypto/md5/#New):
 */

package main

import (
    "crypto/md5"
    "fmt"
    "io"
)

func main() {
    h := md5.New()
    io.WriteString(h, "The fog is getting thicker!")
    fmt.Printf("%x", h.Sum(nil))
}

// [Stephen Hsu] [so/q/2377881] [cc by-sa 3.0]

cht.sh>/php md5

/*
 * php - Using MD5 on login page
 *
 * Simply wrap $_POST['password'] into md5() like so:
 */

$mypassword = md5 ($_POST['password']);

cht.sh>/java md5

/*
 * java - How can I generate an MD5 hash?
 *
 * The MessageDigest class can provide you with an instance of the MD5
 * digest.
 *
 * When working with strings and the crypto classes be sure to always
 * specify the encoding you want the byte representation in. If you just
 * use string.getBytes() it will use the platform default. (Not all
 * platforms use the same defaults)
 */

import java.security.*;

..

byte[] bytesOfMessage = yourString.getBytes("UTF-8");

MessageDigest md = MessageDigest.getInstance("MD5");
byte[] thedigest = md.digest(bytesOfMessage);

/*
 * If you have a lot of data take a look at the .update(byte[]) method
 * which can be called repeatedly. Then call .digest() to obtain the
 * resulting hash.
 *
 * [koregan] [so/q/415953] [cc by-sa 3.0]

cht.sh> /go reverse list

/*
 * How do I reverse an array in Go?
 *
 * Honestly this one is simple enough that I'd just write it out like
 * this:
 */

package main

import "fmt"

func main() {

    s := []int{5, 2, 6, 3, 1, 4}

    for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
        s[i], s[j] = s[j], s[i]
    }

    fmt.Println(s)
}