I need to do a interactive shell programmatically (in Node.js, but any language will do).
The most important is that I want to start a REPL of any language (node, ruby, erlang etc.) and be able to get autocompletion
pri\t
which I want to get output in stderr (for instance)
print() println() printf()
And because it's in language REPL compgen cannot be used.
I've tried many ways but it seems that it fails because shell can't be interactive while opened programmatically.
Launchin /bin/sh -i just yeilds errors like:
bash: cannot set terminal process group (XXXX): Inappropriate ioctl for device
I've heard that I can't start interactive shell without the terminal, but when doing SSH autocompletion does work which means it can be emulated in some way.
I'd appreciate Your help. I can't continue my work without finding a solution to this.
You can emulate a terminal using a pseudoterminal. This is how ssh does it. There's a lot to using a pseudoterminal though and the SO answer box isn't big enough for all of it. So check the man page for pty(7).
Related
Without using sshpass, sshkeys is there any way to do ssh to a remote machine and provide the password through the lua script only.And also to run a shell command in the background on remote machine after sshing.
How should i take password automatically after executing os.execute('ssh user#192.168.14.81')
That function is not supposed to be used like that. os.execute and io.popen are not really meant to be used at all, actually. They're barebones commands for when you need to do things that are not supposed to work this way but you really need to.
They're both based on standard C library and don't have much to offer. And ssh is handling its interaction with users in some not-so-standard way for security reasons. In general you'll have to use non-standard libraries, like luaposix, or attach some C++ libs for system interaction.
In relation to ssh, there is python library parallel-ssh. Older versions did their thing through ugly parsing of outputs, newer seem to reimplement the whole protocol. With enough desire, it'd be possible to make use of those with lua. Or just use python for the task.
Ass for peculiarities of lua interaction with processes, you may try this code (put it in a file as it'll clog stdin if you try pasting it in terminal)
f=io.popen([[
echo "this will show only on f:read";
echo "now here's your line";
read var; echo $var
]]);
print('this will print before bash command finishes, now type something');
f:write('This will be ignored completely')
print(f:read('*a'));
print('This will print after the bash command');
f:close()
Using the Turtle shell scripting library I am trying to launch a program, i.e:
shell "vim" empty
The problem is that this yields the warning Warning: Input is not from a terminal and causes Vim to lag for a few seconds before finally launching.
Questions:
Is shell the best Turtle function to launch an external program from haskell?
If so, is there any way to get around errors like the above?
You want to use functions from the process library, specifically createProcess or runProcess.
Relevant turtle thread on the issue here.
Example usage.
You could try manually setting up I/O to the vty. E.g. in bash: vim < $TTY > $TTY. I guess turtle is doing that with its own file descriptors under the hood, based on the warning, so you should be able to manually set up those redirects (or just use the command I gave via shell). You just need to make sure you've got a TTY environment var around.
I would like to write my own interactive shell for Linux.
limited set of my own commands
no need to execute external binaries
It is not hard to do it, but I would like to do somethimg more user friendly.
TAB auto completion
interactive line editing
history of last commands
Is there some library/framework/minimal shell that can be used for this?
So I don't need to write everything myself.
Prefered license is some permissive (MIT, BSD, Apache, ..)
Prefered language is python, c, c++, javascript or sh
For Python, the standard-library cmd module does this: https://docs.python.org/2.7/library/cmd.html
For C, you have several options available for managing interactive editing, history, and tab completion:
readline, used by bash itself, but GPL-licensed.
editline, a widespread BSD alternative.
linenoise, a newer alternative.
By the way -- this question is explicitly off-topic; I expect it to be closed.
If you need job control (i.e. backgrounding) you can have a look at the glibc manual on Implementing a Shell.
I have to connect to a linux server from my own Ubuntu machine and operate directly on the server.
A dozen of folder names are listed in a LIST file. How to write sth. (like a bash script?) to carry out the following procedures?
for fold_name in LIST {
/******on my own Ubuntu*******/
-- open 2 new tabs of prompt terminal
-- run an ssh command in both
-- then input passwd and log in automatically in both
/******on the linux server*******/
-- cd to directory xxx/fold_name in both
-- run aaa.exe in 1st tab
-- vim sth in the 2nd tab
}
Once the loop of open-tab-login is solved, I guess the second part is routine as simple bash script except that I don't know how to specify between 2 tabs, either.
The point is I want all tabs in the same terminal. To this end, manually, I often Ctrl+Alt+T to create a prompt and Ctrl+Shift+T to open many tabs within it. And ssh...cd...... in each one. You see how annoying and cumbersome it is!
There are a few things you might like to research, which will get you a little closer.
You can run an ssh without a password, if you use an ssh key. Check out ssh-keygen, and the -i option in ssh.
Opening up tabs in gnome-terminal can be done via the method described here: Open a new tab in gnome-terminal using command line
You can run specific commands (e.g. aaa.exe) on a remote box over ssh, by including the command after the ssh: ssh user#remotehost aaa.exe.
If you want multiple commands, try enclosing them in quotes: ssh user#remotehost "cd /xxx; aaa.exe". Vim does not need to be in the directory in question in most cases: ssh user#remotehost vim /xxx/filename"
If you want to do something interactive (like vim), include the -t flag in ssh.
The tabs will be independent of each other - I'd probably run half of the command in one window, the other (e.g. runnning aaa.exe in one window, using one command, and the vim in another window, using another command, that I just happen to run at the same time. This way I can resize the windows, and arrange them relative to each other, and see both at once.
-- open 2 new tabs of prompt terminal
This depends on which desktop you're using. For gnome, gnome-terminal takes the -e option to specify the script to execute in the new terminal window. So, for something like this, you would execute gnome-terminal -e $script &, placing each instance of gnome-terminal in the background.
If you're using a different desktop, other terminal applications typically have a similar option. So, you'd point the terminal application to a script that's going to run in the terminal, and complete the rest of your task for you.
-- run an ssh command in both
-- then input passwd and log in automatically in both
This is going to be more complicated. The classical solution is the expect utility. There might be other similar tools that do similar things, but expect is pretty much the usual way these kinds of things have been done in the past. When it comes to trying to automate an interactive application, expect is really the only way to go. Unfortunately, expect uses a somewhat arkane syntax, that first-time users typically find confusing, and hard to understand. I grumble, every time I see no other alternative but to use expect to automate something, but this is pretty much the only option that's usually available.
I've written a script (that doesn't work) that looks something like this:
#!/bin/sh
screen -dmS "somename" $HOME/somescript.sh
j=13
for i in {0..5}; do
screen -dmS "name$i" $HOME/anotherscript.sh $i $j
j=10
done
If I copy and paste this into a terminal, it creates 7 detached screen sessions, as I expect. If I run it from within a script, however, I get only the first session, "somename," when I run screen -ls.
I realize screen can be used to create multiple windows within one session. It doesn't really matter to me how these scripts get run. I just want to get to the bottom of why this doesn't work as a script.
Note: I've asked this question on SuperUser without any suitable responses. I figured maybe that's the wrong place to ask what could be considered a programming question.
One thing you might be getting bitten on is which specific version of which specific shell you're running. /bin/sh could actually be bash, or it could be bourne, and that can make a difference on how your loop syntax is interpreted. The {0..5} construct isn't understood in older versions of bash (v2.x), for instance, nor in bourne (at least it wasn't when I finally managed to track down a /bin/sh that was a real, live bourne shell :-).
My suggestion is to change your shebang line to /bin/bash if you need its syntax, and check that your bash is version 3.x or later. Since you say it works from the commandline, my bet is on the shebang line, though.