如何在Shell脚本内重定向全量输出并保留终端交互？

需求说明 #

• 需要向终端输出反馈（已尝试| tee /dev/tty）
• 需要支持多种用户输入方式：
  • read -p 'prompt: ' var
  • select yn in "Yes" "No"; do ...
  • 私有仓库git clone时的账号密码输入

当前测试脚本（精简版） #

#/bin/bash
set -e
set -x
{
if lxc list | grep container
then
  :
else
  lxc launch images:ubuntu/20.04 container
  echo 'waiting for networking to be up-and-running...' | tee /dev/tty
  sleep 5
  echo 'installing base system...' | tee /dev/tty
  lxc exec container -- apt update
  lxc exec container -- apt install -y git
  echo "install documentation processor? " | tee /dev/tty
  select yn in "Yes" "No"
  do
    if [ $yn == "Yes" ]
    then
      echo 'installing documentation processor...' | tee /dev/tty
      lxc exec container -- apt install -y wget
      lxc exec container -- wget https://github.com/plantuml/plantuml/releases/download/v1.2022.12/plantuml-1.2022.12.jar -O /usr/local/bin/plantuml.jar
    fi
    break
  done
  read -p 'enter your EMAIL address: ' email | tee /dev/tty
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global user.email "$email"
  read -p 'enter your FULL NAME: ' name | tee /dev/tty
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global user.name "$name"
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global credential.helper store
  echo 'cloning repository...' | tee /dev/tty
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git clone git@github.com:gabime/spdlog.git
  echo "enable audio in container? " | tee /dev/tty
  select yn in "Yes" "No"
  do
    if [ $yn == "Yes" ]
    then
      for dev in $(find /dev/snd -type c)
      do
        lxc config device add container snd_$(basename $dev) unix-char source=$dev path=$dev gid=1000
        lxc exec container -- apt install -y alsa-utils
      done
    fi
    break
  done
fi
} >lxd_build.log 2>&1

现存问题 #

• read -p的提示仅写入日志，终端不可见
• select的交互提示仅写入日志，终端不可见
• git clone的账号密码输入提示终端不可见

解决方案 #

核心思路 #

放弃脚本整体重定向的方式，改为区分非交互命令输出与终端交互流：非交互命令的输出定向到日志，交互相关的提示/输入直接绑定到终端，同时用tee保留终端反馈。

具体修复步骤 #

1. 处理read -p提示
   read -p的提示默认输出到stderr，会被整体重定向吞掉。改为显式将提示输出到终端，再单独读取输入，最后把输入内容写入日志：

# 替代原read写法
echo -n 'enter your EMAIL address: ' > /dev/tty
read email
echo "EMAIL address entered: $email" >> lxd_build.log

2. 处理select交互
   select依赖终端环境，需要临时将其输入输出绑定到终端，同时手动记录选择结果到日志：

# 替代原select写法
echo "install documentation processor? " > /dev/tty
# 绑定select的IO到终端
select yn in "Yes" "No"
do
  if [ "$yn" = "Yes" ]
  then
    echo 'installing documentation processor...' | tee -a lxd_build.log
    # 非交互命令输出定向到日志
    lxc exec container -- apt install -y wget >> lxd_build.log 2>&1
    lxc exec container -- wget https://github.com/plantuml/plantuml/releases/download/v1.2022.12/plantuml-1.2022.12.jar -O /usr/local/bin/plantuml.jar >> lxd_build.log 2>&1
  fi
  # 记录选择结果到日志
  echo "Selected option: $yn" >> lxd_build.log
  break
done < /dev/tty > /dev/tty 2>&1

3. 处理git clone交互
   SSH/HTTPS方式的git clone交互需要绑定终端IO，同时可以用tee兼顾日志记录：

# 替代原git clone写法
echo 'cloning repository...' | tee -a lxd_build.log
lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git clone git@github.com:gabime/spdlog.git 2>&1 | tee -a lxd_build.log

优化后的完整脚本 #

#!/bin/bash
set -e
set -x

LOG_FILE="lxd_build.log"
> "$LOG_FILE" # 清空日志，如需追加改为>>

if lxc list | grep container
then
  :
else
  lxc launch images:ubuntu/20.04 container >> "$LOG_FILE" 2>&1
  echo 'waiting for networking to be up-and-running...' | tee -a "$LOG_FILE"
  sleep 5
  echo 'installing base system...' | tee -a "$LOG_FILE"
  lxc exec container -- apt update >> "$LOG_FILE" 2>&1
  lxc exec container -- apt install -y git >> "$LOG_FILE" 2>&1

  # 处理第一个select交互
  echo "install documentation processor? " > /dev/tty
  select yn in "Yes" "No"
  do
    if [ "$yn" = "Yes" ]
    then
      echo 'installing documentation processor...' | tee -a "$LOG_FILE"
      lxc exec container -- apt install -y wget >> "$LOG_FILE" 2>&1
      lxc exec container -- wget https://github.com/plantuml/plantuml/releases/download/v1.2022.12/plantuml-1.2022.12.jar -O /usr/local/bin/plantuml.jar >> "$LOG_FILE" 2>&1
    fi
    echo "Selected option for documentation processor: $yn" >> "$LOG_FILE"
    break
  done < /dev/tty > /dev/tty 2>&1

  # 处理email输入
  echo -n 'enter your EMAIL address: ' > /dev/tty
  read email
  echo "enter your EMAIL address: $email" >> "$LOG_FILE"
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global user.email "$email" >> "$LOG_FILE" 2>&1

  # 处理姓名输入
  echo -n 'enter your FULL NAME: ' > /dev/tty
  read name
  echo "enter your FULL NAME: $name" >> "$LOG_FILE"
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global user.name "$name" >> "$LOG_FILE" 2>&1

  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git config --global credential.helper store >> "$LOG_FILE" 2>&1

  # 处理git clone
  echo 'cloning repository...' | tee -a "$LOG_FILE"
  lxc exec container --user 1000 --group 1000 --cwd /home/ubuntu --env HOME=/home/ubuntu -- git clone git@github.com:gabime/spdlog.git 2>&1 | tee -a "$LOG_FILE"

  # 处理第二个select交互
  echo "enable audio in container? " > /dev/tty
  select yn in "Yes" "No"
  do
    if [ "$yn" = "Yes" ]
    then
      for dev in $(find /dev/snd -type c)
      do
        lxc config device add container snd_$(basename $dev) unix-char source=$dev path=$dev gid=1000 >> "$LOG_FILE" 2>&1
      done
      lxc exec container -- apt install -y alsa-utils >> "$LOG_FILE" 2>&1
    fi
    echo "Selected option for audio enable: $yn" >> "$LOG_FILE"
    break
  done < /dev/tty > /dev/tty 2>&1
fi

关键说明 #

• 不再使用整体大括号重定向，而是逐个处理命令输出，确保交互流独立于日志流
• tee -a $LOG_FILE实现终端反馈与日志记录的双重输出
• 所有交互操作的IO都绑定到/dev/tty，保证提示和输入正常显示
• 手动记录用户输入内容到日志，确保日志完整性

内容的提问来源于stack exchange，提问作者ZioByte