使用 dialog 和 jq 在 Linux 上编写高效终端 TUI
TUI jq dialog
![](/data/attachment/album/202311/18/071418mc44bs42keebfe1c.png)


### 为何选择文字用户界面（TUI）？


许多人每日都在使用终端，因此，<ruby> 文字用户界面 <rt>  Text User Interface </rt></ruby>（TUI）逐渐显示出其价值。它能减少用户输入命令时的误差，让终端操作更高效，提高生产力。


以我的个人使用情况为例：我每日会通过家用电脑远程连接到我使用 Linux 系统的实体 PC。所有的远程网络连接都通过私有 VPN 加密保护。然而，当我需要频繁重复输入命令进行连接时，这种经历实在令人烦躁。


于是，我创建了下面这个 Bash 函数，从而有所改进：



```
export REMOTE_RDP_USER="myremoteuser"
function remote_machine() {
  /usr/bin/xfreerdp /cert-ignore /sound:sys:alsa /f /u:$REMOTE_RDP_USER /v:$1 /p:$2
}

```

但后来，我发现自己还是频繁地执行下面这条命令（在一行中）：



```
remote_pass=(/bin/cat/.mypassfile) remote_machine $remote_machine $remote_pass

```

这太烦了。更糟糕的是，我的密码被明文存储在我的电脑上（我虽然使用了加密驱动器，但这点依然令人不安）。


因此，我决定投入一些时间，编写一个实用的脚本，从而更好地满足我的基本需求。


#### 我需要哪些信息才能连接到远程桌面？


实际上，要连接到远程桌面，你只需提供少量信息。这些信息需要进行结构化处理，所以一个简单的 JSON 文件就能够满足要求：



```
{"machines": [
  {
  "name": "machine1.domain.com",
  "description": "Personal-PC"
  },
  {
  "name": "machine2.domain.com",
  "description": "Virtual-Machine"
  }
  ],
"remote_user": "MYUSER@DOMAIN",
"title" : "MY COMPANY RDP connection"
}

```

尽管在各种配置文件格式中，JSON 并非最佳选择（例如，它不支持注解），但是 Linux 提供了许多工具通过命令行方式解析 JSON 内容。其中，特别值得一提的工具就是 [jq](https://stedolan.github.io/jq/)。下面我要向你展示如何利用它来提取机器列表：



```
/usr/bin/jq --compact-output --raw-output '.machines[]| .name' \
  $HOME/.config/scripts/kodegeek_rdp.json) \
  "machine1.domain.com" "machine2.domain.com"


```

`jq` 的文档可以在 [这里](https://jqlang.github.io/jq/manual/) 找到。另外，你也可以直接将你的 JSON 文件复制粘贴到 [jq play](https://jqplay.org/)，试用你的表达式，然后在你的脚本中使用这些表达式。


既然已经准备好了连接远程计算机所需的所有信息，那现在就让我们来创建一个美观实用的 TUI 吧。


#### Dialog 的帮助


[Dialog](https://invisible-island.net/dialog/) 是那些你可能希望早些认识的、被低评估的 Linux 工具之一。你可以利用它构建出一个井然有序、简介易懂，并且完美适用于你终端的用户界面。


比如，我可以创建一个包含我喜欢的编程语言的简单的复选框列表，且默认选择 Python：



```
dialog --clear --checklist "Favorite programming languages:" 10 30 7\
  1 Python on 2 Java off 3 Bash off 4 Perl off 5 Ruby off


```

![](/data/attachment/album/202311/18/071514x77uf8703an1307f.png)


我们通过这条命令向 `dialog` 下达了几个指令：


* 清除屏幕（所有选项都以 `--` 开头）
* 创建一个带有标题的复选框（第一个位置参数）
* 决定窗口尺寸（高度、宽度和列表高度，共 3 个参数）
* 列表中的每条选项都由一个标签和一个值组成。


惊人的是，仅仅一行代码，就带来了简洁直观和视觉友好的选择列表。


关于 `dialog` 的详细文档，你可以在 [这里](https://invisible-island.net/dialog/#documentation) 阅读。


#### 整合所有元素：使用 Dialog 和 JQ 编写 TUI


我编写了一个 TUI，它使用 `jq` 从我的 JSON 文件中提取配置详细信息，并且使用 `dialog` 来组织流程。每次运行，我都会要求输入密码，并将其保存在一个临时文件中，脚本使用后便会删除这个临时文件。


这个脚本非常基础，但它更安全，也使我能够专注于更重要的任务 ?


那么 [脚本](https://raw.githubusercontent.com/josevnz/scripts/main/kodegeek_rdp.sh) 看起来是怎样的呢？下面是代码：



```
#!/bin/bash
# Author Jose Vicente Nunez
# Do not use this script on a public computer. It is not secure...
# https://invisible-island.net/dialog/
# Below some constants to make it easier to handle Dialog
# return codes
: ${DIALOG_OK=0}
: ${DIALOG_CANCEL=1}
: ${DIALOG_HELP=2}
: ${DIALOG_EXTRA=3}
: ${DIALOG_ITEM_HELP=4}
: ${DIALOG_ESC=255}
# Temporary file to store sensitive data. Use a 'trap' to remove
# at the end of the script or if it gets interrupted
declare tmp_file=$(/usr/bin/mktemp 2>/dev/null) || declare tmp_file=/tmp/test$$
trap "/bin/rm -f $tmp_file" QUIT EXIT INT
/bin/chmod go-wrx ${tmp_file} > /dev/null 2>&1
:<<DOC
Extract details like title, remote user and machines using jq from the JSON file
Use a subshell for the machine list
DOC
declare TITLE=$(/usr/bin/jq --compact-output --raw-output '.title' $HOME/.config/scripts/kodegeek_rdp.json)|| exit 100
declare REMOTE_USER=$(/usr/bin/jq --compact-output --raw-output '.remote_user' $HOME/.config/scripts/kodegeek_rdp.json)|| exit 100
declare MACHINES=$(
    declare tmp_file2=$(/usr/bin/mktemp 2>/dev/null) || declare tmp_file2=/tmp/test$$
    # trap "/bin/rm -f $tmp_file2" 0 1 2 5 15 EXIT INT
    declare -a MACHINE_INFO=$(/usr/bin/jq --compact-output --raw-output '.machines[]| join(",")' $HOME/.config/scripts/kodegeek_rdp.json > $tmp_file2)
    declare -i i=0
    while read line; do
        declare machine=$(echo $line| /usr/bin/cut -d',' -f1)
        declare desc=$(echo $line| /usr/bin/cut -d',' -f2)
        declare toggle=off
        if [ $i -eq 0 ]; then
            toggle=on
            ((i=i+1))
        fi
        echo $machine $desc $toggle
    done < $tmp_file2
    /bin/cp /dev/null $tmp_file2
) || exit 100
# Create a dialog with a radio list and let the user select the
# remote machine
/usr/bin/dialog \
    --clear \
    --title "$TITLE" \
    --radiolist "Which machine do you want to use?" 20 61 2 \
    $MACHINES 2> ${tmp_file}
return_value=$?
# Handle the return codes from the machine selection in the
# previous step
export remote_machine=""
case $return_value in
  $DIALOG_OK)
    export remote_machine=$(/bin/cat ${tmp_file})
    ;;
  $DIALOG_CANCEL)
    echo "Cancel pressed.";;
  $DIALOG_HELP)
    echo "Help pressed.";;
  $DIALOG_EXTRA)
    echo "Extra button pressed.";;
  $DIALOG_ITEM_HELP)
    echo "Item-help button pressed.";;
  $DIALOG_ESC)
    if test -s $tmp_file ; then
      /bin/rm -f $tmp_file
    else
      echo "ESC pressed."
    fi
    ;;
esac

# No machine selected? No service ...
if [ -z "${remote_machine}" ]; then
  /usr/bin/dialog \
        --clear  \
        --title "Error, no machine selected?" --clear "$@" \
        --msgbox "No machine was selected!. Will exit now..." 15 30
  exit 100
fi

# Send 4 packets to the remote machine. I assume your network
# administration allows ICMP packets
# If there is an error show  message box
/bin/ping -c 4 ${remote_machine} >/dev/null 2>&1
if [ $? -ne 0 ]; then
  /usr/bin/dialog \
        --clear  \
        --title "VPN issues or machine is off?" --clear "$@" \
        --msgbox "Could not ping ${remote_machine}. Time to troubleshoot..." 15 50
  exit 100
fi

# Remote machine is visible, ask for credentials and handle user
# choices (like password with a password box)
/bin/rm -f ${tmp_file}
/usr/bin/dialog \
  --title "$TITLE" \
  --clear  \
  --insecure \
  --passwordbox "Please enter your Windows password for ${remote_machine}\n" 16 51 2> $tmp_file
return_value=$?
case $return_value in
  $DIALOG_OK)
    # We have all the information, try to connect using RDP protocol
    /usr/bin/mkdir -p -v $HOME/logs
    /usr/bin/xfreerdp /cert-ignore /sound:sys:alsa /f /u:$REMOTE_USER /v:${remote_machine} /p:$(/bin/cat ${tmp_file})| \
    /usr/bin/tee $HOME/logs/$(/usr/bin/basename $0)-$remote_machine.log
    ;;
  $DIALOG_CANCEL)
    echo "Cancel pressed.";;
  $DIALOG_HELP)
    echo "Help pressed.";;
  $DIALOG_EXTRA)
    echo "Extra button pressed.";;
  $DIALOG_ITEM_HELP)
    echo "Item-help button pressed.";;
  $DIALOG_ESC)
    if test -s $tmp_file ; then
      /bin/rm -f $tmp_file
    else
      echo "ESC pressed."
    fi
    ;;
esac


```

![](/data/attachment/album/202311/18/071515zwwg76rzjgbqgbz3.png)


你从代码中可以看出，`dialog` 预期的是位置参数，并且允许你在变量中捕获用户的回应。这实际上使其成为编写文本用户界面的 Bash 扩展。


上述的小例子只涵盖了一些部件的使用，其实还有更多的文档在 [官方 dialog 网站](https://invisible-island.net/dialog/)上。


### Dialog 和 JQ 是最好的选择吗？


实现这个功能可以有很多方法（如 [Textual](https://textual.textualize.io/)，Gnome 的 [Zenity](https://gitlab.gnome.org/GNOME/zenity/commits/master?ofs=1900)，Python 的 [TKinker](https://docs.python.org/3/library/tkinter.html)等）。我只是想向你展示一种高效的方式——仅用 100 行代码就完成了这项任务。


*确实，它并不完美*。更具体地讲，它与 Bash 的深度集成使得代码有些冗长，但仍然保持了易于调试和维护的特性。相比于反复复制粘贴长长的命令，这无疑是一个更好的选择。


最后，如果你喜欢在 Bash 中使用 `jq` 处理 JSON，那么你会对这个 [jq 配方的精彩集合](https://nntrn.github.io/jq-recipes/) 感兴趣的。


*（题图：MJ/a9b7f60a-02ec-4d3f-88ae-2321f49ac0e1）*




---


via: <https://fedoramagazine.org/writing-useful-terminal-tui-on-linux-with-dialog-and-jq/>


作者：[Jose Nunez](https://fedoramagazine.org/author/josevnz/) 选题：[lujun9972](https://github.com/lujun9972) 译者：[ChatGPT](https://linux.cn/lctt/ChatGPT) 校对：[wxy](https://github.com/wxy)


本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出


OK
# Why a Text User Interface?

Many use the terminal on a daily basis. A Text User Interface (TUI) is a tool that will minimize user errors and allow you to become more productive with the terminal interface.

Let me give you an example: I connect on a daily basis from my home computer into my Physical PC, using Linux. All remote networking is protected using a private [VPN](https://en.wikipedia.org/wiki/Virtual_private_network). After a while it was irritating to be repeating the same commands over and over when connecting.

Having a bash function like this was a nice improvement:

export REMOTE_RDP_USER="myremoteuser" function remote_machine() { /usr/bin/xfreerdp /cert-ignore /sound:sys:alsa /f /u:$REMOTE_RDP_USER /v:$1 /p:$2 }

But then I was constantly doing this (on a single line):

remote_pass=(/bin/cat/.mypassfile) remote_machine $remote_machine $remote_pass

*That was annoying.* Not to mention that I had my password in clear text on my machine (I have an encrypted drive but still…)

So I decided to spend a little time and came up with a nice script to handle my basic needs.

## What information do I need to connect to my remote desktop?

Not much information is needed. It just needs to be structured so a simple JSON file will do:

{"machines": [ { "name": "machine1.domain.com", "description": "Personal-PC" }, { "name": "machine2.domain.com", "description": "Virtual-Machine" } ], "remote_user": "MYUSER@DOMAIN", "title" : "MY COMPANY RDP connection" }

JSON is not the best format for configuration files (as it doesn’t support comments, for example) but it has plenty of tools available on Linux to parse its contents from the command line. A very useful tool that stands out is [ jq](https://stedolan.github.io/jq/). Let me show you how I can extract the list of machines:

/usr/bin/jq --compact-output --raw-output '.machines[]| .name' \ ($HOME/.config/scripts/kodegeek_rdp.json) \ "machine1.domain.com" "machine2.domain.com"

Documentation for *jq* is available [here](https://jqlang.github.io/jq/manual/). You can try your expressions at [jq play](https://jqplay.org/) just by copying and pasting your JSON files there and then use the expression in your scripts.

So now that I have all the ingredients I need to connect to my remote computer, let’s build a nice TUI for it.

## Dialog to the rescue

[Dialog](https://invisible-island.net/dialog/) is one of those underrated Linux tools that you wish you knew about a long time ago. You can build a very nice and simple UI that will work perfectly on your terminal.

For example, to create a simple checkbox list with my favorite languages, selecting Python by default:

dialog --clear --checklist "Favorite programming languages:" 10 30 7 1 \ Python on 2 Java off 3 Bash off 4 Perl off 5 Ruby off

![](https://fedoramagazine.org/wp-content/uploads/2023/11/dialog-example1.png)


![](https://fedoramagazine.org/wp-content/uploads/2023/11/dialog-example1.png)

We told dialog a few things:

- Clear the screen (all the options start with –)
- Create a checklist with title (first positional argument)
- A list of dimensions (height width list height, 3 items)
- Then each element of the list is a pair of a Label and a value.

Surprisingly is very concise and intuitive to get a nice selection list with a single line of code.

Full documentation for *dialog* is available [here](https://invisible-island.net/dialog/#documentation).

## Putting everything together: Writing a TUI with Dialog and JQ

I wrote a TUI that uses *jq* to extract my configuration details from my JSON file and organized the flow with *dialog*. I ask for the password every single time and save it in a temporary file which gets removed after the script is done using it.

The script is pretty basic but is more secure and also lets me focus on more serious tasks 🙂

So what does the [script](https://raw.githubusercontent.com/josevnz/scripts/main/kodegeek_rdp.sh) looks like? Let me show you the code:

#!/bin/bash # Author Jose Vicente Nunez # Do not use this script on a public computer. It is not secure... # https://invisible-island.net/dialog/ # Below some constants to make it easier to handle Dialog # return codes : ${DIALOG_OK=0} : ${DIALOG_CANCEL=1} : ${DIALOG_HELP=2} : ${DIALOG_EXTRA=3} : ${DIALOG_ITEM_HELP=4} : ${DIALOG_ESC=255} # Temporary file to store sensitive data. Use a 'trap' to remove # at the end of the script or if it gets interrupted declare tmp_file=$(/usr/bin/mktemp 2>/dev/null) || declare tmp_file=/tmp/test$$ trap "/bin/rm -f $tmp_file" QUIT EXIT INT /bin/chmod go-wrx ${tmp_file} > /dev/null 2>&1 :<<DOC Extract details like title, remote user and machines using jq from the JSON file Use a subshell for the machine list DOC declare TITLE=$(/usr/bin/jq --compact-output --raw-output '.title' $HOME/.config/scripts/kodegeek_rdp.json)|| exit 100 declare REMOTE_USER=$(/usr/bin/jq --compact-output --raw-output '.remote_user' $HOME/.config/scripts/kodegeek_rdp.json)|| exit 100 declare MACHINES=$( declare tmp_file2=$(/usr/bin/mktemp 2>/dev/null) || declare tmp_file2=/tmp/test$$ # trap "/bin/rm -f $tmp_file2" 0 1 2 5 15 EXIT INT declare -a MACHINE_INFO=$(/usr/bin/jq --compact-output --raw-output '.machines[]| join(",")' $HOME/.config/scripts/kodegeek_rdp.json > $tmp_file2) declare -i i=0 while read line; do declare machine=$(echo $line| /usr/bin/cut -d',' -f1) declare desc=$(echo $line| /usr/bin/cut -d',' -f2) declare toggle=off if [ $i -eq 0 ]; then toggle=on ((i=i+1)) fi echo $machine $desc $toggle done < $tmp_file2 /bin/cp /dev/null $tmp_file2 ) || exit 100 # Create a dialog with a radio list and let the user select the # remote machine /usr/bin/dialog \ --clear \ --title "$TITLE" \ --radiolist "Which machine do you want to use?" 20 61 2 \ $MACHINES 2> ${tmp_file} return_value=$? # Handle the return codes from the machine selection in the # previous step export remote_machine="" case $return_value in $DIALOG_OK) export remote_machine=$(/bin/cat ${tmp_file}) ;; $DIALOG_CANCEL) echo "Cancel pressed.";; $DIALOG_HELP) echo "Help pressed.";; $DIALOG_EXTRA) echo "Extra button pressed.";; $DIALOG_ITEM_HELP) echo "Item-help button pressed.";; $DIALOG_ESC) if test -s $tmp_file ; then /bin/rm -f $tmp_file else echo "ESC pressed." fi ;; esac # No machine selected? No service ... if [ -z "${remote_machine}" ]; then /usr/bin/dialog \ --clear \ --title "Error, no machine selected?" --clear "$@" \ --msgbox "No machine was selected!. Will exit now..." 15 30 exit 100 fi # Send 4 packets to the remote machine. I assume your network # administration allows ICMP packets # If there is an error show message box /bin/ping -c 4 ${remote_machine} >/dev/null 2>&1 if [ $? -ne 0 ]; then /usr/bin/dialog \ --clear \ --title "VPN issues or machine is off?" --clear "$@" \ --msgbox "Could not ping ${remote_machine}. Time to troubleshoot..." 15 50 exit 100 fi # Remote machine is visible, ask for credentials and handle user # choices (like password with a password box) /bin/rm -f ${tmp_file} /usr/bin/dialog \ --title "$TITLE" \ --clear \ --insecure \ --passwordbox "Please enter your Windows password for ${remote_machine}\n" 16 51 2> $tmp_file return_value=$? case $return_value in $DIALOG_OK) # We have all the information, try to connect using RDP protocol /usr/bin/mkdir -p -v $HOME/logs /usr/bin/xfreerdp /cert-ignore /sound:sys:alsa /f /u:$REMOTE_USER /v:${remote_machine} /p:$(/bin/cat ${tmp_file})| \ /usr/bin/tee $HOME/logs/$(/usr/bin/basename $0)-$remote_machine.log ;; $DIALOG_CANCEL) echo "Cancel pressed.";; $DIALOG_HELP) echo "Help pressed.";; $DIALOG_EXTRA) echo "Extra button pressed.";; $DIALOG_ITEM_HELP) echo "Item-help button pressed.";; $DIALOG_ESC) if test -s $tmp_file ; then /bin/rm -f $tmp_file else echo "ESC pressed." fi ;; esac

![](https://fedoramagazine.org/wp-content/uploads/2023/11/dialog-example2.png)


![](https://fedoramagazine.org/wp-content/uploads/2023/11/dialog-example2.png)

You can see from the code that *dialog* expects positional arguments and also allows you to capture user responses in variables. This effectively makes it an extension to Bash to write text user interfaces.

My small example above only covers the usage of some of the Widgets, there is plenty more documentation on the [official dialog site](https://invisible-island.net/dialog/).

## Are dialog and JQ the best options?

You can skin this rabbit in many ways ([Textual](https://textual.textualize.io/), Gnome [Zenity](https://gitlab.gnome.org/GNOME/zenity/commits/master?ofs=1900), Python [TKinker](https://docs.python.org/3/library/tkinter.html), etc.) I just wanted to show you one nice way to accomplish this in a short time, with only 100 lines of code.

*It is not perfect*. Specficially, integration with Bash makes the code very verbose, but it is still easy to debug and maintain. This is also much better than copying and pasting the same long command over and over.

One last thing: If you liked *jq* for JSON processing from Bash, then you will appreciate this [nice collection of jq recipes](https://nntrn.github.io/jq-recipes/).

## Greater Productivity

NICE!

## Thomas

I have similar functions in my .bashrc to handle connections to different aws accounts, connect to different machines using a different tool called

(https://github.com/tmonjalo/choose) that is itself made of just 377 lines of bash.

## james

It looks great, and I will definitely investigate Dialog. I am using gtkdialog for other purposes currently, and the version I am using, whilst great, is a bit dated.

But where you say:

‘But then I was constantly doing this (on a single line):’

Could you not use an alias? Or two, one for each machine? And use openssl or similar to encrypt your password?

Just a thought. If I were going to adopt a bash script like the one above, I might write it in a process agnostic manner, so that it could handle any json file, with perhaps a schema file processed to address the json needing to be displayed in dialog. Save reinventing the wheel, so to speak…

## Jose Nunez

Hi, glad that you liked the small article. I don’t want to make it agnostic, only to work with RDP . An alias for every machine sounds great if you have 2 machines, when you have 10, well not so great. Also the TUI allows me to make changes on the password if I make a typo.

## John

For temp credentials in a txt file, I “>” to it while the script needs it. I end my routine using “wipe” on said txt file to ensure total clean up. Even if it takes a bit for the script to exit which in the case of a simple text file it only takes seconds.

## Jose Nunez

That works too, great idea. I mention on the article than my disk has encryption so it felt over-killing to add this there.

## xenlo

Typo detected!

%s/I connect on a daily basics/I connect on a daily basis/g

😋

## Richard England

TY, corrected.

## Jose Nunez

Thanks for the correction!

## Bryan

The idea of a TUI isn’t bad in itself, but in the year 2023 you should probably consider not allowing services using a password on the Internet. Even if you are capable of generating good passwords, average humans aren’t.

Try doing something like this instead:

https://swjm.blog/the-complete-guide-to-rdp-with-yubikeys-fido2-cba-1bfc50f39b43

## Jose Nunez

Hello Bryan, thanks for the link.

Your link focuses mostly on Windows, the readers may want to take a look at this:

https://fedoramagazine.org/fido2-for-centrally-managed-users/

And guess what, you still need to type a pin to use it, so there is still justification to write a small TUI wrapper around it 🙂

## Andrew L. Moore

Fedora Magazine isn’t the venue to report code bugs, but I think this one’s worth flagging: the statement

declare foo=$(false) || echo failed

does not report “failed” as one might expect. That’s because `declare’ only fails if it’s given an invalid option or if the variable assignment fails – not if the statement fails. The correct way to write this is:

declare foo=”

foo=$(false) || echo failed

It’s also generally a good idea to wrap code in functions and then call the functions at the end of the script. Happy hacking 🙂

## Jose Nunez

Hello Andrew,

You are correct, declaration of variables and testing should be separate to avoid the issue you mention above. Or something like:

if ! foo=$(false); then

echo false

fi

Or even:

set -x # Stop everything after the first error.

## tertol

I need to try this dialog. This will add an extra help my bash. Thanks for the info

## wololo

jq is one of the finest pieces of software I know.

Not a fan of dialog, just a shell script and it shows.