创建一个写入多个文件的管道 (tee)

Question

我想在 ksh 脚本（使用 exec）中创建一个管道，该管道连接到 tee，并将输出发送到管道。

当前：

#Redirect EVERYTHING
exec 3>&1 #Save STDOUT as 3
exec 4>&2 #Save STDERR as 4
exec 1>${Log} #Redirect STDOUT to a log
exec 2>&1 #Redirect STDERR to STDOUT

我喜欢做什么（但我的语法不正确）：

#Redirect EVERYTHING
exec 3>&1 #Save STDOUT as 3
exec 4>&2 #Save STDERR as 4
exec 1>tee -a ${Log} >&3  #Redirect STDOUT to a log
exec 2>&1 #Redirect STDERR to STDOUT

如何创建这个管道？

Answer 1

我知道 bash 不是 ksh，但有很多重叠，所以也许这也可以。

process1 N> >(process2)

创建一个子shell运行进程2。该 subshel​​l 接收来自 process1 的文件描述符 N 的数据作为其标准输入。所以特别是，您可以这样做：

process1 1> >(tee -a mylog >&3)

我不知道如果将process1 替换为exec 是否也可以，但你可以尝试一下。

Answer 2

在 ksh 中有 |& 和 >&p，但我无法让它们执行您想要的操作。也许你可以。

Answer 3

代替：

exec 1>tee -a ${Log} >&3

简单地做：

tee -a ${Log} >&3 &

tee 将分叉到后台，并像 tee 分叉时一样使用调用进程（即您的脚本）的 STDIN。

Answer 4

我使用named pipes 制定了一个解决方案。

#!/bin/ksh

LOG=~/testLog.log
PIPE=~/logPipe
mkfifo ${PIPE}
exec 3>&1 #Save STDOUT as 3
exec 4>&2 #Save STDERR as 4
tee -a ${LOG} <${PIPE} >&3 & #Start tee off the logpipe in the background
exec 1>${PIPE} #Redirect stdout to the pipe
exec 2>&1 #Redirect STDERR to STDOUT

echo "TEST"
echo Test 2

ls | grep -i "test"

rm -f ${PIPE} #Remove the pipe

Answer 5

这是我使用的解决方案。它在我的 Mac 上的 ksh 下工作。它很好地封装在 start_logging() 和 stop_logging() 函数中，让生活更轻松。

代码在实践中是这样的：

# Optional:
#   Set the name and location of the log file.
#   OUTPUT_LOG=output.log    # default
#   Set the name and location of the named pipe used.
#   OUTPUT_PIPE=output.pipe  # default

start_logging
# Default is to append to an existing log file.
# start_logging delete_existing_logfile
echo "This is on standard out"
echo "This is on standard err" >&2
stop_logging

这是整个文件。 start 和 stop 函数以及上面的示例都在文件的底部。为了使其更易于使用，只需将启动和停止函数放在它们自己的文件中，然后在需要日志记录的脚本中获取它们。

#!/bin/sh

# Author: Harvey Chapman <hchapman _AT_ 3gfp.com>
# Description: POSIX shell functions that can be used with tee to simultaneously put
#              stderr and stdout to both a file and stdout
#
# Based on:
#    Re: How to redirect stderr and stdout to a file plus display at the same time
#    http://www.travishartwell.net/blog/2006/08/19_2220

#
# Original example function from Travis Hartwell's blog.
# Note: I've made minor changes to it.
example()
{
  OUTPUT_LOG=output.log
  OUTPUT_PIPE=output.pipe

  # This should really be -p to test that it's a pipe.
  if [ ! -e $OUTPUT_PIPE ]; then
      mkfifo $OUTPUT_PIPE
  fi

  # This should really be -f to test that it's a regular file.
  if [ -e $OUTPUT_LOG ]; then
      rm $OUTPUT_LOG
  fi

  exec 3>&1 4>&2
  tee $OUTPUT_LOG < $OUTPUT_PIPE >&3 &
  tpid=$!
  exec > $OUTPUT_PIPE 2>&1

  echo "This is on standard out"
  echo "This is on standard err" >&2

  exec 1>&3 3>&- 2>&4 4>&-
  wait $tpid

  rm $OUTPUT_PIPE
}

# A slightly reduced version of example()
example2()
{
  OUTPUT_LOG=output.log
  OUTPUT_PIPE=output.pipe

  rm -f $OUTPUT_PIPE
  mkfifo $OUTPUT_PIPE
  rm -f $OUTPUT_LOG

  tee $OUTPUT_LOG < $OUTPUT_PIPE &
  tpid=$!

  exec 3>&1 4>&2 >$OUTPUT_PIPE 2>&1

  echo "This is on standard out"
  echo "This is on standard err" >&2

  exec 1>&3 3>&- 2>&4 4>&-
  wait $tpid
  rm -f $OUTPUT_PIPE
}

#
# Logging methods based on above. See the example below for how to use them.
#

# Usage: start_logging [delete_existing_logfile]
start_logging()
{
  # Check to see if OUTPUT_LOG and OUTPUT_PIPE need to be defined.
  if [ -z "$OUTPUT_LOG" ]; then
    OUTPUT_LOG=output.log
  fi
  if [ -z "$OUTPUT_PIPE" ]; then
    OUTPUT_PIPE=output.pipe
  fi
  # Make sure that we're not already logging.
  if [ -n "$OUTPUT_PID" ]; then
    echo "Logging already started!"
    return 1
  fi

  # Always remove the log and pipe first.
  rm -f $OUTPUT_PIPE
  # Delete the logfile first if told to.
  if [ "$1" = delete_existing_logfile ]; then
    rm -f $OUTPUT_LOG
  fi

  mkfifo $OUTPUT_PIPE
  tee -a $OUTPUT_LOG < $OUTPUT_PIPE &
  OUTPUT_PID=$!

  exec 3>&1 4>&2 >$OUTPUT_PIPE 2>&1
}

stop_logging()
{
  # Make sure that we're currently logging.
  if [ -z "$OUTPUT_PID" ]; then
    echo "Logging not yet started!"
    return 1
  fi
  exec 1>&3 3>&- 2>&4 4>&-
  wait $OUTPUT_PID
  rm -f $OUTPUT_PIPE
  unset OUTPUT_PID
}

example3()
{
  start_logging
  #start_logging delete_existing_logfile
  echo "This is on standard out"
  echo "This is on standard err" >&2
  stop_logging
}

#example
#example2
example3