I want to use ruby and in one moment open another program (cfdisk) and let the user interact with it, then return to my code
I can use
exec "cfdisk; ruby another.rb"
but that is very hacky and certainly not the right thing to do
I know about Open3 but i dont know how to use it properly for my usecase. I know that when I use capture3 on irb on Windows it says:
["Running under a virtual console, enabling 256/true-color support\n", "Screen size 28640x499 is not supported; limit 500x500.\nCheck the TERM environment variable.\n", #]
In Arch it opens it but the graphical output isnt present, the keystrokes are registered, they work (for example mc exits with F10) but the window isnt there, just blinking cursor.
parted exits immediately
Tried popen3 but I had no luck with it either
What is wrong with system for this case?
The exec ruby command replaces the running process, so it will not return to your code.
The Open3 library is used when you want to capture stdout and stderr.
Isn't this what you are looking for?
puts "here"
system "cfdisk"
puts 'there'
If you have some screen related issues, this is another issue that you might be able to resolve with different TERM value in the environment variable.
Related
I'm using go's exec Run command to get command output, which works great when the command 'Stdout' field is set to os.Stdout, and the error is sent to os.Stderr.
I want to display the output and the error output to the console, but I also want my program to see what the output was.
I then made my own Writer type that did just that, wrote both to a buffer and printed to the terminal.
Here's the problem—some applications change their output to something much less readable by humans when it detects it's not writing to a tty. So the output I get changes to something ugly when I do it in the latter way. (cleaner for computers, uglier for humans)
I wanted to know if there was some way within Go to convince whatever command I'm running that I am a tty, despite not being os.Stdout/os.Stderr. I know it's possible to do using the script bash command, but that uses a different flag depending on Darwin/Linux, so I'm trying to avoid that.
Thanks in advance!
The only practical way to solve this is to allocate a pseudo terminal (PTY) and make your external process use it for its output: since PTY is still a terminal, a process checking whether it's connected to a real terminal thinks it is.
You may start with this query.
The github.com/creack/ptyis probably a good starting point.
The next step is to have a package implementing a PTY actually allocate it, and connect "the other end" of a PTY to your custom writer.
(By the way, there's no point in writing a custom "multi writer" as there exist io.MultiWriter).
(Please, help me adjust title and tags.)
When I run connmanctl I get a different prompt,
enrico:~$ connmanctl
connmanctl>
and different commands are available, like services, technologies, connect, ...
I'd like to know how this thing works.
I know that, in general, changing the prompt can be just a matter of changing the variable PS1. However this thing alone (read "the command connmanctl changes PS1 and returns) wouldn't have any effect at all on the functionalities of the commands line (I would still be in the same bash process).
Indeed, the fact that the available commands are changed, looks to me like the proof that connmanctl is running all the time the prompt is connmanctl>, and that, upon running connmanctl, a while loop is entered with a read statement in it, followed by a bunch of commands which process the the input.
In this latter scenario that I imagine, there's not even need to change PS1, as the connmanctl> line could simply be obtained by echo -n "connmanctl> ".
The reason behind this curiosity is that I'm trying to write a wrapper to connmanctl. I've already written it, and it works as intended, except that I don't know how to properly setup the autocompletion feature, and I think that in order to do so I first need to understand what is the right way to write an interactive shell script.
I have a shell running in a Vte.Terminal widget (could be bash, zsh, or any other interactive shell), I would like to monitor it so as to know when the prompt is available and a new command can be started.
I can't seem to come up with a consistent method.
Here are the ideas I've thought of so far:
Monitor for child process exit.
Could work some of the time, but commands that use only built-ins wouldn't spawn a child. (example: "while true; do; echo test; done;") Also When a command is started in background the prompt would be available before the child exited.
Watch for prompt string in Vte output.
Two problems: 1. A simple prompt string such as "#>" could easily be outputted by some script and give a false positive. 2. Knowing what the prompt string is, is problematic.
Any other ideas or a way to get one of the above working?
What my purpose is.
I'm working on a terminal emulator and would like to change the icon based on whether the prompt is available. Also I am attempting to allow commands to be 'queued' to run when next possible.
I would like to talk to a interactive bash process.
Here is an example, so you know what I want to archieve:
Program starts a new bash process.
User types "ls" into my program.
Program sends this command to the bash process.
Program reads all available output of the bash (including the prompt) and displays it back to the user.
GOTO 1
As you can guess, there is much room for nifty manipulations here and there... ;-)
It would be wonderful if this also worked for subprocesses (started by the bash process) and curses-based programs.
I would like to implement this functionality in Ruby, and already have experimented with IO.popen, but strange things happen. You are also welcome to do this in other languages.
Ok, I've found a solution. This work pretty nicely, you can even start vim inside it :-)
require "pty"
system("stty raw -echo")
PTY.spawn("bash -i") do |pin, pout|
Thread.new do
loop do
pout.print STDIN.getc.chr
end
end
loop do
print pin.sysread(512)
STDOUT.flush
end
end
This does the following:
enable character-wise input (limited to UNIXoids, I'm afraid)
create a pseudo-TTY, start a interactive bash session inside
forward each character from STDIN to the bash
print every output back to the user
Have you tried using the Session gem?
http://rubygems.org/gems/session
https://github.com/ahoward/session (Homepage with introduction.)
I don't have any experience with it, but the README seems to describe what you want. It's description says, "session kicks the ass", so it should be fun/productive to play with it in any case.
I'm playing around with making a simple terminal-based game with Ruby, and I'm currently trying to come up with a way of reading input from the terminal.
So far I've been using gets, but I'd like to have the game react instantly without requiring a newline (so you don't need to press a key, THEN enter).
I've figured out I need to put the terminal in non-canonical mode, and I'm assuming I can do that by calling $stdin.ioctl. The problem is, I'm not sure what arguments or flags I should be passing to this, and the documentation and searches just lead to information about the underlying C function.
Can anyone tell me what I should be calling $stdin.ioctl with? I'm using Terminal.app/tcsh on OSX Leopard.
Edit: This is what I ended up using, thanks to MarkusQ:
%x{stty -icanon -echo}
key = STDIN.read(1)
Your problem is outside of ruby.
Easiest answer: wrap your IO in %x{stty -raw echo} and %x{stty -raw echo} to change the mode with stty.
You'll probably want to do and ensure an exit handler to make certain the mode is set back when you exit.
-- MarkusQ