Call lua function from bash

Question

I have a lua-script, named "program.lua". I start this script as 'lua /path/to/program.lua' and I get specific CLI provided by the script:

bash $ /usr/bin/lua /path/to/program.lua
Usage: 
  help   - help
  quit   - quit
  do_get - get data
script> _

In this script I have function 'do_get', and if I call this function from the program.lua's CLI, I've got the correct output:

bash $ /usr/bin/lua /path/to/program.lua
Usage: 
  help   - help
  quit   - quit
  do_get - get data
script> do_get
string1
string2
param1
param2

script> _

The question. How I can call function 'do_get' from bash and get the output I need without entering to script's CLI?

The script edit is disallowed.

Thank you

This isn't really a Lua question, as you're not changing the Lua script. Also, what you're calling isn't a function in the Lua sense. — DarkWiiPlayer
– DarkWiiPlayer, Commented Nov 27, 2020 at 10:54

pce · Accepted Answer · 2020-11-26 16:39:02Z

1

You can capture the output by calling the Lua Program in a shell-script and pipe the output to a variable:

lua_output=$(printf "do_get\n\n" | /usr/bin/lua /path/to/program.lua 2>&1)
 
echo $lua_output

If that does not work try a tool that can handle interactive prompts like yes (https://man7.org/linux/man-pages/man1/yes.1.html) yes do_get | /usr/bin/lua /path/to/program.lua or expect (https://man7.org/linux/man-pages/man1/expect.1.html)

edited Nov 26, 2020 at 16:39

answered Nov 26, 2020 at 13:28

pce

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4 Comments

Andrii K. Over a year ago

No. I've edited the question and provided more information why I can't launch the script directly from the bash

pce Over a year ago

@AndriiK. ok, i've upodated my answer

pce Over a year ago

@AndriiK. did you try running the example?

pce Over a year ago

@AndriiK. i've updated the answer, you need to handle the interavtive prompt. Try to pipe or a tool like yes or expect, expect will work.

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