bash your_script.sh 1>file.log 2>&1

1> log指示shell将标准输出发送到file.log文件，2>&1告诉它将标准错误（文件描述符2）重定向到标准输出（文件描述符1）。

注意：正如liw.fi指出的那样，顺序很重要，2>&11>file.log不起作用。

对于需要“管道”的情况，可以使用|&。

例如：

echo -ne "15\n100\n" | sort -c |& tee >sort_result.txt

or

TIMEFORMAT=%R;for i in `seq 1 20` ; do time kubectl get pods | grep node >>js.log ; done |& sort -h

这些基于Bash的解决方案可以分别处理标准输出和标准错误（从标准错误“sort-c”，或从标准错误到“sort-h”）。

您可以将stderr重定向到stdout，并将stdout重定向到文件中：

some_command >file.log 2>&1

见第20章。I/O重定向

这种格式比最流行的仅适用于Bash的&>格式更受欢迎。在Bourne shell中，它可以解释为在后台运行命令。格式也更可读-2（标准错误）重定向为1（标准输出）。

除了费南多·法布雷蒂所做的，我稍微改变了一下功能，去掉了&关闭，这对我来说很有用。

    function saveStandardOutputs {
      if [ "$OUTPUTS_REDIRECTED" == "false" ]; then
        exec 3>&1
        exec 4>&2
        trap restoreStandardOutputs EXIT
      else
          echo "[ERROR]: ${FUNCNAME[0]}: Cannot save standard outputs because they have been redirected before"
          exit 1;
      fi
  }

  # Parameters: $1 => logfile to write to
  function redirectOutputsToLogfile {
      if [ "$OUTPUTS_REDIRECTED" == "false" ]; then
        LOGFILE=$1
        if [ -z "$LOGFILE" ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: logfile empty [$LOGFILE]"
        fi
        if [ ! -f $LOGFILE ]; then
            touch $LOGFILE
        fi
        if [ ! -f $LOGFILE ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: creating logfile [$LOGFILE]"
            exit 1
        fi
        saveStandardOutputs
        exec 1>>${LOGFILE}
        exec 2>&1
        OUTPUTS_REDIRECTED="true"
      else
        echo "[ERROR]: ${FUNCNAME[0]}: Cannot redirect standard outputs because they have been redirected before"
          exit 1;
      fi
  }

  function restoreStandardOutputs {
      if [ "$OUTPUTS_REDIRECTED" == "true" ]; then
      exec 1>&3   #restore stdout
      exec 2>&4   #restore stderr
      OUTPUTS_REDIRECTED="false"
     fi
  }

  LOGFILE_NAME="tmp/one.log"
  OUTPUTS_REDIRECTED="false"

  echo "this goes to standard output"
  redirectOutputsToLogfile $LOGFILE_NAME
  echo "this goes to logfile"
  echo "${LOGFILE_NAME}"
  restoreStandardOutputs
  echo "After restore this goes to standard output"

在考虑使用exec2>&1之类的情况下，如果可能的话，我发现使用如下Bash函数重写代码更容易阅读：

function myfunc(){
  [...]
}

myfunc &>mylog.log

以下函数可用于自动切换stdout/stderr和日志文件之间的输出。

#!/bin/bash

    #set -x

    # global vars
    OUTPUTS_REDIRECTED="false"
    LOGFILE=/dev/stdout

    # "private" function used by redirect_outputs_to_logfile()
    function save_standard_outputs {
        if [ "$OUTPUTS_REDIRECTED" == "true" ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: Cannot save standard outputs because they have been redirected before"
            exit 1;
        fi
        exec 3>&1
        exec 4>&2

        trap restore_standard_outputs EXIT
    }

    # Params: $1 => logfile to write to
    function redirect_outputs_to_logfile {
        if [ "$OUTPUTS_REDIRECTED" == "true" ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: Cannot redirect standard outputs because they have been redirected before"
            exit 1;
        fi
        LOGFILE=$1
        if [ -z "$LOGFILE" ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: logfile empty [$LOGFILE]"

        fi
        if [ ! -f $LOGFILE ]; then
            touch $LOGFILE
        fi
        if [ ! -f $LOGFILE ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: creating logfile [$LOGFILE]"
            exit 1
        fi

        save_standard_outputs

        exec 1>>${LOGFILE%.log}.log
        exec 2>&1
        OUTPUTS_REDIRECTED="true"
    }

    # "private" function used by save_standard_outputs() 
    function restore_standard_outputs {
        if [ "$OUTPUTS_REDIRECTED" == "false" ]; then
            echo "[ERROR]: ${FUNCNAME[0]}: Cannot restore standard outputs because they have NOT been redirected"
            exit 1;
        fi
        exec 1>&-   #closes FD 1 (logfile)
        exec 2>&-   #closes FD 2 (logfile)
        exec 2>&4   #restore stderr
        exec 1>&3   #restore stdout

        OUTPUTS_REDIRECTED="false"
    }

脚本内部用法示例：

echo "this goes to stdout"
redirect_outputs_to_logfile /tmp/one.log
echo "this goes to logfile"
restore_standard_outputs 
echo "this goes to stdout"