I am trying to start composer-rest-server in background using following command :
composer-rest-server &
Its getting started as background process, but then process is getting stuck after displaying "hyperledger-Composer" banner as :
Is there anyway we can start composer-rest-server as background process?
Run command like this:
nohup composer-rest-server -c <network card name> -n never -w true > rest-server.out 2> rest-server.err < /dev/null &
all standard output will be saved in rest-server.out and errors in rest-server.err
& at the end will put it in background and you will get PID
Next time you connect to server and if you want to kill earlier instance then use ps -A | grep "node" command to get PID.
If you run it with no arguments it will prompt for arguments (reading from the keyboard). You should launch it with arguments. If you run it with no arguments from a terminal, answering all the questions, at the end it will print the command line you can use to launch it with the answers suppplied using command line arguments.
You should be able to use that command line with nohup or screen or similar.
Related
I am working with ROS. And for starting ros-packages you need to have the ROS Master run in the background. Now when I want to start the ROS-package rviz, instead of opening two terminals:
Terminal1:
$ roscore
Terminal2:
$ rviz
I can do the follwing in one Terminal:
$ roscore& rviz
But what exactly is happening here? Because when I end that terminal with Str+C it only closes rivz, but roscore is kept running in the background? Why and how can I close it?
in case using single & the left side will run in the background, while the right side will run normally in the terminal.
Now to close the first process you need to find PID (Process ID) and do the termination command, so first of all you need to find PID and you can use pgrep (in your case PROCESS_NAME can be roscore):
pgrep -f PROCESS_NAME
Now to kill the process you can easily do:
kill -9 PID_HERE
Or you can do it by single command:
pgrep -f PROCESS_NAME | xargs kill -9
My script needs root privileges and I want to run it on a remote machine and then be able to turn off my local computer.
So I did:
$ nohup sudo ./myScript arg1 &
... which I always do, but on a different machine where I'm always root, so without sudo. For some reason now it's not working:
nohup sudo ./myScript.sh 1 & //then I press enter twice
[8] 24264
me#my-laptop:~/myFolder$ nohup: ignoring input and appending output to `nohup.out'
[8]+ Stopped nohup sudo ./myScript.sh 1
What am I doing wrong here?
Try this:
sudo nohup ./script
After answering the password prompt, type Ctrl-z to suspend it, and bg to put it into the background.
This is especially helpful if you are half-way through running a long process when you decide it needs to be run in the background.
As mentioned in other answers, if a background process started with nohup tries to read from or write to the terminal, it is put into the "Stopped" state. The sudo process that you're executing tries to read your password from the terminal, so the process is stopped (for some reason, the reading seems to be triggered when Enter is pressed).
So, to avoid this, you ned to make sure to enter your password and become root before nohup is executed. For example, like this:
sudo bash -c 'nohup ./myScript.sh arg1 &'
One option here is use the screen utility. Start screen, run your script, detach using CTRL+A, D. Later, log back in, reconnect to the process by running screen again.
I have a previously running process (process1.sh) that is running in the background with a PID of 1111 (or some other arbitrary number). How could I send something like command option1 option2 to that process with a PID of 1111?
I don't want to start a new process1.sh!
Named Pipes are your friend. See the article Linux Journal: Using Named Pipes (FIFOs) with Bash.
Based on the answers:
Writing to stdin of background process
Accessing bash command line args $# vs $*
Why my named pipe input command line just hangs when it is called?
Can I redirect output to a log file and background a process at the same time?
I wrote two shell scripts to communicate with my game server.
This first script is run when computer start up. It does start the server and configure it to read/receive my commands while it run in background:
start_czero_server.sh
#!/bin/sh
# Go to the game server application folder where the game application `hlds_run` is
cd /home/user/Half-Life
# Set up a pipe named `/tmp/srv-input`
rm /tmp/srv-input
mkfifo /tmp/srv-input
# To avoid your server to receive a EOF. At least one process must have
# the fifo opened in writing so your server does not receive a EOF.
cat > /tmp/srv-input &
# The PID of this command is saved in the /tmp/srv-input-cat-pid file
# for latter kill.
#
# To send a EOF to your server, you need to kill the `cat > /tmp/srv-input` process
# which PID has been saved in the `/tmp/srv-input-cat-pid file`.
echo $! > /tmp/srv-input-cat-pid
# Start the server reading from the pipe named `/tmp/srv-input`
# And also output all its console to the file `/home/user/Half-Life/my_logs.txt`
#
# Replace the `./hlds_run -console -game czero +port 27015` by your application command
./hlds_run -console -game czero +port 27015 > my_logs.txt 2>&1 < /tmp/srv-input &
# Successful execution
exit 0
This second script it just a wrapper which allow me easily to send commands to the my server:
send.sh
half_life_folder="/home/jack/Steam/steamapps/common/Half-Life"
half_life_pid_tail_file_name=hlds_logs_tail_pid.txt
half_life_pid_tail="$(cat $half_life_folder/$half_life_pid_tail_file_name)"
if ps -p $half_life_pid_tail > /dev/null
then
echo "$half_life_pid_tail is running"
else
echo "Starting the tailing..."
tail -2f $half_life_folder/my_logs.txt &
echo $! > $half_life_folder/$half_life_pid_tail_file_name
fi
echo "$#" > /tmp/srv-input
sleep 1
exit 0
Now every time I want to send a command to my server I just do on the terminal:
./send.sh mp_timelimit 30
This script allows me to keep tailing the process on your current terminal, because every time I send a command, it checks whether there is a tail process running in background. If not, it just start one and every time the process sends outputs, I can see it on the terminal I used to send the command, just like for the applications you run appending the & operator.
You could always keep another open terminal open just to listen to my server server console. To do it just use the tail command with the -f flag to follow my server console output:
./tail -f /home/user/Half-Life/my_logs.txt
If you don't want to be limited to signals, your program must support one of the Inter Process Communication methods. See the corresponding Wikipedia article.
A simple method is to make it listen for commands on a Unix domain socket.
For how to send commands to a server via a named pipe (fifo) from the shell see here:
Redirecting input of application (java) but still allowing stdin in BASH
How do I use exec 3>myfifo in a script, and not have echo foo>&3 close the pipe?
You can use the bash's coproc comamnd. (avaliable only in 4.0+) - it's like ksh's |&
check this for examples http://wiki.bash-hackers.org/syntax/keywords/coproc
you can't send new args to a running process.
But if you are implementing this process or its a process that can take the args from a pipe, then the other answer would help.
my bash script reads in a few variables and then runs airodump on my home network. I would like to keep the window with airodump running and open some new terminals to run other commands for network discovery while the airodump screen is open (so i can see the results).
right now what i have looks like this (edited for brevity):
#!/bin/bash
read -p "Enter the channel: $channel"
airomon-ng start wlan0 $channel,$channel
airodump-ng -c $channel,$channel mon0 &&
terminator -e netstat -ax &&
terminator -e nmap 192.168.1.1
the first command that uses the whole terminal (airodump) starts up fine and i can see the network, but then it just stays on that screen. If i ctrl+c then it goes back to prompt but i can see the error : Usage: terminator [options] error no such option
i want the netstat and nmap commands to appear and stay in their own terminal windows, how can i do this?
The terminal window is generated by a separate program from the command running inside. Try one of these variations:
xterm -e airomon-start wlan0 "$channel","$channel" &
gnome-terminal -x airomon-start wlan0 "$channel","$channel" &
konsole -e airomon-start wlan0 "$channel","$channel" &
Pick the command that invokes the terminal program you like. You'll have to do this for every command that you want run in its own window. Also, you need to use a single & at the end of each such command line -- not a double && -- those do totally different things. And the last line of your script should be just
wait
that makes it not exit out from under all the terminals, possibly causing them all to die.
Obligatory tangential shell-scripting nitpick: ALWAYS put shell variable uses inside double quotes, unless you know for a fact that you need word-splitting to happen on a particular use.
If the script is running in the foreground in the terminal, then it will pause while an interactive command is using the terminal. You could change the script to run airodump in a new terminal as well, or you could run the background commands before you start airodump (maybe after sleeping, if you're concerned they won't work right if run first?)
I ssh to another server and run a shell script like this nohup ./script.sh 1>/dev/null 2>&1 &
Then type exit to exit from the server. However it just hangs. The server is Solaris.
How can I exit properly without hanging??
Thanks.
I assume that this script is a long running one. In this case you need to detach the process from the terminal that you wish to close when you terminate your ssh session.
Actually you already done most of the work by reassigning both stdout and stderr to /dev/null, however you didn't do that for stdin.
I used the test case of:
ssh localhost
nohup sleep 10m &> /dev/null &
^D
# hangs
While
ssh localhost
nohup sleep 10m &> /dev/null < /dev/null &
^D
# exits
I second the recommendation to use the excellent gnu screen, that will do this service for you, among others.
Oh, and have you considered running the script directly and not within a shell? I.e.:
ssh user#host script.sh
If you're trying to leave a command running remotely after you close your SSH link, I strongly recommend you use screen and learn to detach the screen. That's much better than leaving background processes around; it also lets you reconnect and see what the process is up to.
Since you haven't provided us with script.sh, I don't think we can know for sure why the command is hanging.
You can use the command :
~.
This command close the ssh session.
sh -c ./script.sh &