有点全，但不是很全。

一次读入，分批次读入，缓存读入。

要记得这几种不同读取的应用场景。

package main

import (
"bufio"
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
)

func main() {
if len(os.Args) != 2 {
fmt.Println("Please specify a path.")
return
}

b1, err := ioutil.ReadFile(os.Args\[1\])
if err != nil {
    fmt.Println("Error: ", err)
}

fmt.Println(string(b1))

f1, err := os.Open(os.Args\[1\])
if err != nil {
    fmt.Println("Error: ", err)
}

defer f1.Close()

var (
    b2 = make(\[\]byte, 16)
)

for n := 0; err == nil; {
    n, err = f1.Read(b2)
    if err == nil {
        fmt.Print(string(b2\[:n\]))
    }
}
for err != nil && err != io.EOF {
    fmt.Println("\\n\\nError: ", err)
}

var b3 = bytes.NewBuffer(make(\[\]byte, 26))

var texts = \[\]string{
    \`As he came into the window\`,
    \`It was the sound of a crescendo

He came into her apartment`,
`He left the bloodstains on the carpet`,
`She ran underneath the table
He could see she was unable
So she ran into the bedroom
She was struck down, it was her doom`,
}

for i := range texts {
    b3.Reset()
    b3.WriteString(texts\[i\])
    fmt.Println("Length: ", b3.Len(), "\\tCapacity: ", b3.Cap())
}

f2, err := os.Open(os.Args\[1\])
if err != nil {
    fmt.Println("Error: ", err)
}

defer f2.Close()

r := bufio.NewReader(f2)
var rowCount int
for err == nil {
    var b4 \[\]byte
    for moar := true; err == nil && moar; {
        b4, moar, err = r.ReadLine()
        if err == nil {
            fmt.Print(string(b4))
        }
    }
    if err == nil {
        fmt.Println()
        rowCount++
    }
}
if err != nil && err != io.EOF {
    fmt.Println("\\nError: ", err)
    return
}
fmt.Println("\\nRow count: ", rowCount)

}