A set of libraries like ncurses in a shell script

Question

Supose you present the following TUI in the shell:

I need a set of libraries that can be used in the shell to do it. Being sure, ncurses has not been used, because it make a dependecy.

Question: How to build the widget/window or another TUI in the shell?

Solution 1

Okay, I feel like you might be asking one of two questions, so I will try to answer both.

1. What libraries can one use to create ncurses like interfaces for shell scripts?

   Actually, I would never have recommended ncurses directly for shell scripts anyway since it's really not meant to be used by shell languages. Instead, I would recommend dialog. Dialog is a shim library which sits between ncurses and the shell making its use much simpler.

   This would functionally give you two dependencies (one on ncurses and one on dialog) which you seem to be against for some reason.

2. Given that I don't want any external dependencies, how can I create my own ncurses-like TUI library?

   This is way outside the scope of *nix.SE. Creating a new TUI library is not going to be trivial (particularly if you're trying to create it in pure shell). There have been plenty of projects to attempt making new libraries to replace some of the use of ncurses (e.g., termbox is one of the more successful ones).

   If you intend to create your own library, you may want to look at the lower-level projects like ncurses and termbox and higher-level projects like dialog. Looking at their work might give you an idea of how to get started.

---

A final recommendation:

Dependencies on external projects, though they require some extra work (for integration and support), are not a bad thing. It means that you can focus only on the tool you want to make and leave the ground-work to those doing the lower infrastructure. Linux, in particular out of the *nix platforms, has a long history of dependency interaction.

If your goal is to learn how the lower-level stuff is done, great go for it. If instead you're trying to make a tool that would benefit from such low level work, just depend on an external tool. You'll be happier and so will be everyone that looks at your code.

Solution 2

#/bin/bash
      E='echo -e';e='echo -en';trap "R;exit" 2
    ESC=$( $e "\e")
   TPUT(){ $e "\e[${1};${2}H";}
  CLEAR(){ $e "\ec";}
  CIVIS(){ $e "\e[?25l";}
   DRAW(){ $e "\e%@\e(0";}
  WRITE(){ $e "\e(B";}
   MARK(){ $e "\e[7m";}
 UNMARK(){ $e "\e[27m";}
      R(){ CLEAR ;stty sane;$e "\ec\e[37;44m\e[J";};
   HEAD(){ DRAW
           for each in $(seq 1 13);do
           $E "   x                                          x"
           done
           WRITE;MARK;TPUT 1 5
           $E "BASH SELECTION MENU                       ";UNMARK;}
           i=0; CLEAR; CIVIS;NULL=/dev/null
   FOOT(){ MARK;TPUT 13 5
           printf "ENTER - SELECT,NEXT                       ";UNMARK;}
  ARROW(){ read -s -n3 key 2>/dev/null >&2
           if [[ $key = $ESC[A ]];then echo up;fi
           if [[ $key = $ESC[B ]];then echo dn;fi;}
     M0(){ TPUT  4 20; $e "Login info";}
     M1(){ TPUT  5 20; $e "Network";}
     M2(){ TPUT  6 20; $e "Disk";}
     M3(){ TPUT  7 20; $e "Routing";}
     M4(){ TPUT  8 20; $e "Time";}
     M5(){ TPUT  9 20; $e "ABOUT  ";}
     M6(){ TPUT 10 20; $e "EXIT   ";}
      LM=6
   MENU(){ for each in $(seq 0 $LM);do M${each};done;}
    POS(){ if [[ $cur == up ]];then ((i--));fi
           if [[ $cur == dn ]];then ((i++));fi
           if [[ $i -lt 0   ]];then i=$LM;fi
           if [[ $i -gt $LM ]];then i=0;fi;}
REFRESH(){ after=$((i+1)); before=$((i-1))
           if [[ $before -lt 0  ]];then before=$LM;fi
           if [[ $after -gt $LM ]];then after=0;fi
           if [[ $j -lt $i      ]];then UNMARK;M$before;else UNMARK;M$after;fi
           if [[ $after -eq 0 ]] || [ $before -eq $LM ];then
           UNMARK; M$before; M$after;fi;j=$i;UNMARK;M$before;M$after;}
   INIT(){ R;HEAD;FOOT;MENU;}
     SC(){ REFRESH;MARK;$S;$b;cur=`ARROW`;}
     ES(){ MARK;$e "ENTER = main menu ";$b;read;INIT;};INIT
  while [[ "$O" != " " ]]; do case $i in
        0) S=M0;SC;if [[ $cur == "" ]];then R;$e "\n$(w        )\n";ES;fi;;
        1) S=M1;SC;if [[ $cur == "" ]];then R;$e "\n$(ifconfig )\n";ES;fi;;
        2) S=M2;SC;if [[ $cur == "" ]];then R;$e "\n$(df -h    )\n";ES;fi;;
        3) S=M3;SC;if [[ $cur == "" ]];then R;$e "\n$(route -n )\n";ES;fi;;
        4) S=M4;SC;if [[ $cur == "" ]];then R;$e "\n$(date     )\n";ES;fi;;
        5) S=M5;SC;if [[ $cur == "" ]];then R;$e "\n$($e by oTo)\n";ES;fi;;
        6) S=M6;SC;if [[ $cur == "" ]];then R;exit 0;fi;;
 esac;POS;done

Comments

[Admin]

There's a curses module for zsh. Here's a quick demo: zsh.org/mla/users/2019/msg00317.html

[PersianGulf]

Thanks, 1. i'm not going create a new lib. 2. I'm not going make a dependency such as ncurses. 3. i checked, dialog dpeend on libncursesw5 . 4. I guess if i want to use same lib, i want to use Terminfo , May be i extract tasksel , or mysql-server packages, because they have preconfigure script and dont' have any dependency. anyway thank you.

[Jakob Bennemann]

I really don't understand why you're against depending on ncurses…

[PersianGulf]

ncurses one of stable library which exist is. But when terminfo is exist, Why make i a dependecy?

[Jakob Bennemann]

I guess it depends on what you want to do. Doing things by-hand in terminfo can be a bit of a nightmare (though the same might be said of ncurses).

[Marius]

Very likely terminfo on your system is a part of ncurses, in any case.

[user394]

"though they require some extra work" they are well worth it, considering the payoff, or else they wouldn't have existed as a thing for so long in programming.