如何使用"coproc"与另一个命令驱动程序进行交互 [英] How to use 'coproc' to interact with another command driven program

问题描述

好吧，显然我不是bash大师，需要一个！

Ok, obviously I am NOT a bash guru and am in need of one!

我以前从未使用过'coproc'，但这似乎正是我所需要的.但是，我必须承认，我无法从各种"ping"示例中推断出！[我尝试了几个小时...]

I have never used 'coproc' before, but it seems to be just what I need. But, I have to admit that I can not extrapolate from the various 'ping' examples out there! [I did try for a couple of hours...]

我要做的就是启动一个"coproc" shell脚本，该脚本可以从标准输入中获取输入并将其结果写到标准输出中.我希望主脚本分别发送和处理这些命令和结果.

All I want to do is to start a 'coproc' shell script that can take input from standard in and writes it's results to standard out. I want the main script to do the sending and processing of those commands and results respectively.

这是我尝试做的最简单的概述之一:使用更详细的内容进行编辑

Here is one of the simplest outlines of what I am trying to do: EDITED WITH BETTER DETAIL

#! /bin/bash

coproc bkgndProc {
    /some/path/to/usefulScript.sh  maybeSomeArgsHere
}

// send command #1 to bkgndProc here
result=$(echo 'command' <&${bkgndProc[0]})    ### Doesn't work for me
echo "Did it work? $result"   ### this just prints back the 'command' I used

// here execute conditional logic based on result:
// if result1; then
//     send command #2 here, getting results
// else
//     send command #3 here, again getting results
// fi

很抱歉使用上面的伪代码，但是我不确定那些发送命令应该是什么！如果有人可以提供详细信息，将不胜感激！

Sorry about using pseudo-code above, but I'm not sure what those sending commands should be! If anyone could supply the details that would be greatly appreciated!

推荐答案

result = $(echo 'command' <&${bkgndProc[0]})    ### Doesn't work for me

至少基本上不会工作，因为上面有空格

wouldn't work at least basically since you have spaces on it

result=$(echo 'command' <&${bkgndProc[0]})

----更新----

---- Update ----

一个简单的概念可以显示在这样的脚本中:

A simple concept could be shown in a script like this:

#!/bin/bash

# create the co-process
coproc myproc {
    bash
}

# send a command to it (echo a)
echo 'echo a' >&"${myproc[1]}"

# read a line from its output
read line <&"${myproc[0]}"

# show the line
echo "$line"

输出:

a

另一个使用超时读取多行的代码:

Another which reads multiple lines using a timeout:

#!/bin/bash

coproc myproc {
    bash
}

# send a command to message 4 random numbers in 4 lines
echo 'echo "$RANDOM"; echo "$RANDOM"; echo "$RANDOM"; echo "$RANDOM"' >&"${myproc[1]}"

# keep reading the line until it times out
while read -t 1 -u "${myproc[0]}" line; do
    echo "$line"
done

输出:

17393
1423
8368
1782

如果我们使用 cat ，它将不再退出，因为另一端仍处于活动状态且已连接，并且尚未达到EOF.这就是我们使用超时的原因.

If we use cat, it would no longer quit since the other end is still alive and connected, and EOF is not yet reached. It's the reason why we used timeouts.

cat <&"${myproc[0]}"

这篇关于如何使用"coproc"与另一个命令驱动程序进行交互的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！