How to run a command line command from a nelua file

[ghost]

by "command line command" i mean commands like
"cd", "mkdir", "ls", "nelua.bat", etc

[stefanos82]

I'm on Linux and the following code works just fine for me:

require 'os'

os.execute('clear') -- clears terminal.

[ghost]

Works for me also, thanks

[edubart]

You can run command line commands like in Lua, using the os or io modules, you could check Lua documentation or tutorials on how to do that. You are probably looking into using os.execute in case you want to execute a command without capturing its output, or io.popen in case you want to capture the output of a command.

Here is a small example:

require 'os'
require 'io'

-- Run a command, the output will go to terminal `stdout`.
os.execute('ls')

-- Run a command, the output will go to string `out`.
local f = assert(io.popen('ls'))
local out = assert(f:read('a'))
f:close()
print(out)

[ghost]

Thanks, i just needed the one without the output for now, but the one which captures output is going to be helpful for the compile bot.

[ghost]

-- run.nelua
require 'os'
require 'io'

local output_file: filestream

local run = io.popen("nelua code.nelua")
local output = run:read('a')

output_file = io.open("output.txt", "w+")
output_file:write(output)
output_file:flush()

output_file:close()
run:close()

-- code.nelua
print("Hello World"

1. If i compile and run run.nelua, it would print in the console that there's an error in code.nelua even though i don't have any print statement in run.nelua.
2. the errors which are printed in the console are not in output.txt

So is there a way to capture the output even if the compilation of the nelua file fails?

[ghost]

Never Mind, I found a workaround

[edubart]

Never Mind, I found a workaround

One way I workaround this is by executing a command while saving the output to a file like:

os.execute("command > command_stdout 2> command_stderr")

This will save stdout to command_stdout file and stderr to command_stderr file, you can then read it.

[ghost]

that's the exact workaround I'm using 😅

"nelua code.nelua > output.txt 2> error.txt"