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"

奇怪的是，这是有效的：

yourcommand &> filename

但这会产生语法错误：

yourcommand &>> filename
syntax error near unexpected token `>'

您必须使用：

yourcommand 1>> filename 2>&1

do_something 2>&1 | tee -a some_file

这会将标准错误重定向到标准输出，将标准输出重定向到some_file并将其打印到标准输出。

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。

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"

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）。