When I try to connect to an Erlang shell using the following command:
to_erl /tmp/erlang.pipe.1
The output of the command is something like this:
Attaching to /tmp/erlang.pipe.1 (^D to exit)
(search)`':
(node#mypc)1>
What is that "(search)`':"?
I use the following command to start the Erlang node to attach to:
run_erl -daemon /tmp/ /tmp "erl -sname node"
I think it is the shell search history mentioned in item OTP-10739 here. I think this should be considered a bug and be reported as such to the erlang-patches mailinglist.
Related
Hello i was trying to issue some distributed erlang commands such as erl -sname/erl -name and i do not get a response.
If i put . at the end it says syntax error.
If i don't it won't return anything and it will treat it like an unfinished command.
I thought this is only for these commands but it seems there are others that will not do anything like
erl -man <module_name>.
Do i need to set something up to be able to issue erl commands.
P.S OS is Windows 10.
The erl command (with or without -sname) is simply how you run Erlang from a console window like cmd or powershell. On Windows, to get a fully working Erlang shell with command line editing etc, you need to use the special werl executable instead of erl - this is due to how Windows consoles work. Try opening a cmd or powershell windows and see how it works.
If you open the properties of the icon you have used for starting Erlang, you will see that the command it is running is werl (from the Start menu you have to use "more -> open file path" to find the actual icon first). You can edit this and add options like -sname yournodename to the command, or you can create a copy of the icon (e.g. to your desktop) and give it a more suitable name, like "My Erlang node", and then edit its options.
I am trying to create an application that can run on two different machines on the same network, and when one of the applications crahes, I want to use erlang heartbeat system to make it restart. How can I do this?
I've read the documentation, but have not figured out how to achieve this in practice.
Thanks
Did you specifically read http://erlang.org/doc/man/heart.html and try to follow the instructions there? In particular, you have to first set the environment variable HEART_COMMAND to the full command line to be used to restart your system.
To make this easier, you could use a launch script like this:
#!/bin/sh
erl -detached -heart -env HEART_COMMAND "$0 $#" -env HEART_BEAT_TIMEOUT 20 -sname mynode
In some environments (such as embedded systems) you might prefer a full OS reboot, and could simply run something like this:
#!/bin/sh
erl -detached -heart -env HEART_COMMAND "reboot" -env HEART_BEAT_TIMEOUT 20 -sname mynode
Part of setting up my ejabberd server includes running ejabberdctl debug and entering some commands. Instead, I would like to have a file that is executed, but have it run from the same context of the ejabberdctl debug REPL. How can I do this?
You can use the rpc:call command. The Node value is what you see at the debug prompt "name#host".
Also, make sure the escript sets the appropriate cookie value.
Let me clarify, if the debug environment looked like this:
(ejabberd#host)1>
You can create a escript file which looks like this. This updates the log level:
#!/usr/bin/env escript
%%! -sname script1 -setcookie cookie -hidden
main([Level]) ->
rpc:call('ejabberd#host', ejabberd_loglevel, set, [list_to_atom(Level)]).
How to create new node? i try some like here
how to run this erlang example
and find the same in tutorial
http://www.erlang.org/doc/reference_manual/distributed.html when i write
% erl -name dilbert
my compiler behaves i forgot '.' at the end. Of course i try end, result the same.
Any ideas?
The command erl -name dilbert is not meant to be typed into the Erlang shell; it's the command you run to start a distributed node instead of plain erl.
(If you really want to turn a running node into a distributed node, you can use net_kernel:start/1, but I've never had a reason to do that except in tests.)
In Linux, you can type erl -name dilbert in the terminal.
In Windows you run it in CMD.
I'm working on creating a single command that will run mulitple things on the command line of another machine. Here is what I'm looking to do.
Use psexec to access remote machine
travel to proper directory and file
execute ant task
exit cmd
run together in one line
I can run the below command from Run to complete what I need accomplished but can't seem to get the format correct for psexec to understand it.
cmd /K cd /d D:\directory & ant & exit
I've tried appling this to the psexec example below:
psexec \\machine cmd /K cd /d D:\directory & ant & exit
When executing this it will activate the command line and travel to D:\directory but won't execute the remaining commands. Adding "" just creates more issues.
Can anyone guide me to the correct format? Or something other than psexec I can use to complete this (free options only)?
Figured it out finally after some more internet searching and trial and error. psexec needs /c to run multiple commands, but that syntax doesn't work with the setup I wrote above. I've gotten the below command to run what I need.
psexec \\machine cmd /c (^d:^ ^& cd directory^ ^& ant^)
I don't need to exit because psexec will exit itself upon completion. You can also use && to require success to continue on to the next command. Found this forum helpful
http://forum.sysinternals.com/psexec_topic318.html
And this for running psexec commands
http://ss64.com/nt/psexec.html
This works:
psexec \ComputerName cmd /c "echo hey1 & echo hey2"
For simple cases I use:
PsExec \\machine <options> CMD /C "command_1 & command_2 & ... & command_N"
For more complex cases, using a batch file with PsExec's -c switch may be more suitable:
The -c switch directs PsExec to copy the specified executable to the remote system for execution and delete the executable from the remote system when the program has finished running.
PsExec \\machine <options> -c PSEXEC_COMMANDS.cmd <arguments>
Since you asked about other options and this has tag configuration managment-- I guess you may be interested in Jenkins (or Hudson). It provide very good way of creating master-slave mechanism which may help in simplifying the build process.
I always use like this way :) and works properly
psexec \\COMPUTER -e cmd /c (COMMAND1 ^& COMMAND2 ^& COMMAND3)