英文:
Golang - reading user input from stdin after reading already
问题
我想能够完全从标准输入中读取内容，然后再从标准输入获取输入。我可以读取发送到我的代码的输入，但是无法读取用户输入。有没有什么办法解决这个问题？我正在编写一个分页工具时遇到了这个问题。
以下是一部分代码，它从标准输入读取内容，然后尝试读取输入。当先读取标准输入时，ReadString('\n') 不会等待，结果是一个长度为零的字符串。如果先调用 ReadString，但没有进行初始的标准输入读取，ReadString 就会正确等待。第二次调用时我得到了 EOF。我会研究一下并看看我能做些什么。
var r = bufio.NewReader(os.Stdin)
var contents string
var err error
contents, err = io.ReadAll(r)
if err != nil {
panic(err)
}
text, err := r.ReadString('\n')
if err != nil {
fmt.Println(err)
}
fmt.Println(text)
希望对你有帮助！
英文:
I would like to be able to read fully from stdin and then get input, also from stdin. I can read the input sent to my code but then I can't read user input. Is there any way around this? I'm doing this as part of a paging tool I am writing.
Read incoming
scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
sb.WriteString(fmt.Sprintf("%s\n", scanner.Text()))
}
Reading user input
reader := bufio.NewReader(os.Stdin)
text, _ := reader.ReadString('\n')
Here is part of the code that reads from stdin then tries to read from input. When stdin is read first ReadString('\n') does not wait and results in a zero length string. If ReadString is read but the initial read from stdin is not made ReadString waits properly. I get EOF in the second call. I'll look into this and see what I can do.
var r = bufio.NewReader(os.Stdin)
var contents string
var err error
contents, err = io.ReadAll(r)
if err != nil {
panic(err)
}
text, err := r.ReadString('\n')
if err != nil {
fmt.Println(err)
}
fmt.Println(txt)
答案1
得分: 2
我的代码首先从标准输入(stdin)读取任何输入。我使用cat命令将文本发送到程序。当我这样做时，我可以从标准输入读取输入，但如果我尝试使用reader.ReadString('\n')或fmt.Scanln()读取键入的输入，就无法获取到任何内容。
你是这样运行程序的：cat file.txt | program，然后你尝试输入更多内容并尝试读取它。
程序的标准输入(stdin)通常继承自父进程。如果你是从交互式shell运行的，那么标准输入(stdin)来自终端（即键盘）。
cat file.txt | program将标准输入(stdin)重定向为从cat的输出中读取。标准输入(stdin)不再指向终端的输入。
你需要重新打开一个与终端的流并向其写入。你可以通过读取/dev/tty来实现这一点。tty, err := os.Open("/dev/tty")。
英文:
> My code first reads any input from stdin. I use cat to send text to the program. When I do that I can read the input from stdin but if I then try to read typed in input using reader.ReadString('\n') or fmt.Scanln() nothing is picked up.
You're running your program like cat file.txt | program and then you're typing more input and trying to read that, too.
A program's stdin is normally inherited from the parent process. If you're running from an interactive shell, that's input from the terminal (ie. the keyboard).
cat file.txt | program redirects stdin to read from the output of cat. Stdin no longer points at the input from the terminal.
You'll have to reopen a stream to the terminal and write to that. You do this by reading from /dev/tty. tty, err := os.Open("/dev/tty").
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