I often at home on the 2nd floor and I keep an eye on the (open) groundfloor gardendoors by webcam and these scripts.
First I connect to the remote system with $sh ~/.camconn which contains:
sshpass -f 'passw' ssh -X name#remoteip '~/webcam5050'
the remote file ~/webcam5050 contains:
#! /bin/sh
cvlc -vvv v4l2:// --sout '#transcode{vcodec=mjpg,vb=2000,width=320,height=240,venc=ffmpeg}:duplicate{dst=standard{access=http,mux=mpjpeg,dst=0.0.0.0:5050/video.mpjpeg}
After a 5 to 6 seconds wait, I start the local webcam viewer $sh ~/compaqcam, containing.:
cvlc http://remoteip:5050/video.mpjpeg
and bingo: I get a nice VLC window on the desktop.
Of course I would like this all to happen with one command and I tried without avail:
#!/bin/bash
(camcon &) && (sleep 8 &) && (compaqcam &) &
A tiny bit of succes with I had with this script:
#!/bin/bash
(sshpass -f 'passw' ssh -X name#remoteip '~/webcam5050'&) && (sleep 8 &) && (cvlc http://remoteip:5050/video.mpjpeg &) &
which at least does show "sshd (accepted)" on the remote, but then nothing further happens.
Can one point me in the right direction?
If so I would be very(!) gratefull since my bash manuals (4pcs) failed me in this case.
I don't have your setup but I suspect the issue is the & after the sleep, which is going to put it into the background so it'll complete immediately, I think your script can just be:
#!/bin/bash
camcon &
sleep 8
compaqcam &
You could still do it on one line without the & after your sleep 8 but this way is clearer and easier to edit in the future.
!/bin/bash
camcon &
sleep 8
compaqcam &
did the trick, along with ssh-keygen and ssh-copy-id.
Thanks a lot!
Related
I have written a bash script to keep a ffmpeg command up and running
#!/bin/bash
while :
do
echo `ffmpeg -re -i http://domain.com/index400.m3u8 -vcodec copy -acodec copy -f mpegts udp://127.0.0.1:10000?pkt_size=1316`
done
The problem is, sometimes the input is broken, yet ffmpeg does not exit when that happens so that it is restarted by the above script. Instead what happens is the same process is kept running eventhough it is not transferring any packet to the UDP address (output). And I need to manually go into the terminal and kill it (kill -9 #processID)
I need a way to make ffmpeg kill its own process whenever the input is broken.
Appreciate your help.
I am used to using linux terminals and nohup over ssh to issue commands that run in the background even when logged out of the ssh session. For some reason nohup seems to be broken in the latest MACOS. For that reason I am trying to executing this small sample script using screen command.
sleep 10
echo "this is my test file" > testfile
This file is saved as tst script. And then I issue the following command.
ssh sohaib#localhost screen -dm sh testscript
However nothing happens. screen just exits quietly without writing to the file testfile.
If I run this without ssh it works as desired. What am I doing wrong here?
The issue is that after your script exits the screen exits. The -dm is for deamons, i.e., scripts that keep running.
Showing the screen exiting after 10 seconds:
On remote host (file is executable):
ttucker#merlin:~$ cat test.sh
#!/bin/bash
echo derp > /tmp/test.txt
sleep 10
Command on local machine:
[ttucker#localhost ~]$ ssh ttucker#merlin 'screen -dmS my_screen ~/test.sh'
After run.
On remote machine, a few seconds after screen is running:
ttucker#merlin:~$ screen -ls
There is a screen on:
23141.my_screen (11/21/2016 07:05:11 PM) (Detached)
1 Socket in /var/run/screen/S-ttucker.
On remote machine, over 10 seconds later:
ttucker#merlin:~$ screen -ls
No Sockets found in /var/run/screen/S-ttucker.
Modifying the script to keep running, and so, keeping the screen up:
If you are really running a script that needs to stay up you can do the following in the script:
#!/bin/bash
while true; do
# Do something
sleep 10
done
This will do something, wait 10 seconds, then loop again.
Or, detaching the screen manually:
You can ssh to the remote machine, run screen, then press Ctrl+A,D, press Ctrl and hold, then hit A then hit D. You can now exit the SSH session and the screen will stay running.
Background:
I'm trying to figure out how to use ConfigFS to set up an HID device on BeagleBoneBlack.
I found the following example (www.isticktoit.net/?p=1383) on the web and tried it. The sample runs on a Raspberry Pi Zero. However, the sample does not work on my BBB. The following is the script that I wrote and which is executed as root. The script attempts to define a keyboard hid device.
#!/bin/bash
cd /sys/kernel/config/usb_gadget/
modprobe libcomposite
modprobe usb_f_hid
mkdir -p isticktoit
cd isticktoit
echo 0x1d6b > idVendor # Linux Foundation
echo 0x0104 > idProduct # Multifunction Composite Gadget
echo 0x0100 > bcdDevice # v1.0.0
echo 0x0200 > bcdUSB # USB2
mkdir -p strings/0x409
echo "fedcba9876543210" > strings/0x409/serialnumber
echo "Tobias Girstmair" > strings/0x409/manufacturer
echo "iSticktoit.net USB Device" > strings/0x409/product
mkdir -p configs/c.1/strings/0x409
echo "Config 1: ECM network" > configs/c.1/strings/0x409/configuration
echo 250 > configs/c.1/MaxPower
# Add functions here
pwd
mkdir -p functions/hid.xyz
echo 1 > functions/hid.xyz/protocol
echo 1 > functions/hid.xyz/subclass
echo 8 > functions/hid.xyz/report_length
echo -ne \\x05\\x01\\x09\\x06\\xa1\\x01\\x05\\x07\\x19\\xe0\\x29\\xe7\\x15\\x00\\x25\\x01\\x75\\x01\\x95\\x08\\x81\\x02\\x95\\x01\\x75\\x08\\x81\\x03\\x95\\x05\\x75\\x01\\x05\\x08\\x19\\x01\\x29\\x05\\x91\\x02\\x95\\x01\\x75\\x03\\x91\\x03\\x95\\x06\\x75\\x08\\x15\\x00\\x25\\x65\\x05\\x07\\x19\\x00\\x29\\x65\\x81\\x00\\xc0 > functions/hid.xyz/report_desc
ln -s functions/hid.xyz configs/c.1/
# End functions
ls /sys/class/udc > UDC
The error that I get is "ls: write error: Devicew or resource busy".
I am running Debian Jessie - Linux version 4.4.9-ti-r25
I did an lsmod and libcomposite and usb_f_hid are loaded.
The usb device controller, musb-hdrc-0.auto, is loaded.
Questions:
How can I tell which device is busy?
Where can I find the USB configfs defect bug list for BBB.
Is there a logging file and enabling parameter that would give me a clue as to what is happening?
Thanks for any help
David Glaser
The problem you are likely having with the beaglebone black is the cdc_acm driver. It is difficult to remove (well, not really now that I KNOW how to do it) if you don't know how because the steps aren't just laid out to find anywhere yet. I found this: https://media.defcon.org/DEF%20CON%2023/DEF%20CON%2023%20presentations/DEFCON-23-Phil-Polstra-One-device-to-Pwn-them-all.pdf
which led me to the following solution
#!/usr/bin/env bash
function checkModule(){
MODULE="$1"
if lsmod | grep "$MODULE" &> /dev/null ; then
echo "$MODULE" found.
return 0
else
echo "$MODULE" not found.
return 1
fi
}
if which 'systemctl' | grep "systemctl" &> /dev/null ; then
systemctl stop serial-getty#ttyGS0.service >/dev/null
fi
if checkModule "g_serial" == 0; then
modprobe -r g_serial
fi
if checkModule "usb_f_acm" == 0; then
modprobe -r usb_f_acm
fi
if ! checkModule "libcomposite" == 0; then
modprobe libcomposite
fi
basically, it stops the serial-getty service which allows you to remove the g_serial device and then this allows you to remove usb_f_acm. This in turn removes the libcomposite device, which you actually want to keep. Once this is done, you can likely do all the things you needed to do. I got a nice HID keyboard working this way (well, okay I guess its a KeygleBone Black now)... It is pretty dirt simple once you understand ALL of the pieces, but I'm having a little trouble tearing my device back down. I might not need to eventually, but I'd like to be able to do that and it seems that certain directories cannot be removed (namely the "strings" directories that I've created). This means I can't really fully tear down the device, but maybe I only need to:
echo "" > /sys/kernel/config/usb_gadget/my_gadget/UDC
to actually tear it down. I haven't worked that part out yet. There are also some C libraries, but I've got a bunch of python scripts that I want to use and I don't yet have python wrappers for those. But that probably isn't too much work.
I didn't want to forget to mention, that I tried to throw the above script into rc.local so the beaglebone black I am using would be "HID ready" on boot. There are probably better locations and methods to do this, but I just wanted to use rc.local because the above is a script, rc.local is a script, it should run on boot... But it doesn't... You have to make sure to make rc.local runable ( chmod 755 /etc/rc.local ) as well as modifying the default shell it wants to run (well, it always runs bash, but its method for running bash is the "POSIX" method, and that doesn't seem to work, so you have to force it to run bash in non-POSIX mode with:
#!/usr/bin/bash
Again, there are probably other better methods (I was lazy here and, well, I'm just old school), especially if your device is going to be an IoT device or anything linked to the net, so you might want to consider something else if you need this script to run on boot.
I did stupidly leave out one thing: I made sure the beaglebone black doesn't present its usual "disk" portion as well. I would put the details here, but frankly, those I'd have to track back down. I basically googled around for how to disable the beaglebone black disk. It isn't hard and amounted to me moving some file to another name so it doesn't find the "USB disk" configuration on boot. You can also change a line in the uboot config somewhere I believe, but I didn't really want to do that.
Found the file: /var/local/bb_usb_mass_storage.img
Well, it might be bbg_usb_mass_storage.img if it is a beaglebone green, but I just moved this file so it wouldn't present the mass storage device. That should allow you to do what you want.
I'm trying to make a push notification work on my debian vps (apace2, mysql).
I use a php script from this tutorial (http://www.raywenderlich.com/3525/apple-push-notification-services-tutorial-part-2).
Basically, the script is put in an infintive loop, that check a mysql table for new records every couple of seconds. The tutorial says it should be run as a background process.
// This script should be run as a background process on the server. It checks
// every few seconds for new messages in the database table push_queue and
// sends them to the Apple Push Notification Service.
//
// Usage: php push.php development &
So I have four questions.
How do I start the script from the terminal? What should I type? The script location on the server is:
/var/www/development_folder/scripts/push2/push.php
How can I kill it if I need to (without having to restart apace)?
Since the push notification is essential, I need a way to check if the script is running.
The code (from the tutorial) calls a function is something goes wrong:
function fatalError($message)
{
writeToLog('Exiting with fatal error: ' . $message);
exit;
}
Maybe I can put something in there to restart the script? But It would also be nice to have a cron job or something that check every 5 minute or so if the script is running, and start it if it doens't.
4 - Can I make the script automatically start after a apace or mysql restart? If the server crash or something else happens that need a apace restart?
Thanks a lot in advance
You could run the script with the following command:
nohup php /var/www/development_folder/scripts/push2/push.php > /dev/null &
The nohup means that that the command should not quit (it ignores hangup signal) when you e.g. close your terminal window. If you don't care about this you could just start the process with "php /var/www/development_folder/scripts/push2/push.php &" instead. PS! nohup logs the script output to a file called nohup.out as default, if you do not want this, just add > /dev/null as I've done here. The & at the end means that the proccess will run in the background.
I would only recommend starting the push script like this while you test your code. The script should be run as a daemon at system-startup instead (see 4.) if it's important that it runs all the time.
Just type
ps ax | grep push.php
and you will get the processid (pid). It will look something like this:
4530 pts/3 S 0:00 php /var/www/development_folder/scripts/push2/push.php
The pid is the first number you'll see. You can then run the following command to kill the script:
kill -9 4530
If you run ps ax | grep push.php again the process should now be gone.
I would recommend that you make a cronjob that checks if the php-script is running, and if not, starts it. You could do this with ps ax and grep checks inside your shell script. Something like this should do it:
if ! ps ax | grep -v grep | grep 'push.php' > /dev/null
then
nohup php /var/www/development_folder/scripts/push2/push.php > /dev/null &
else
echo "push-script is already running"
fi
If you want the script to start up after booting up the system you could make a file in /etc/init.d (e.g. /etc.init.d/mypushscript with something like this inside:
php /var/www/development_folder/scripts/push2/push.php
(You should probably have alot more in this file)
You would also need to run the following commands:
chmod +x /etc/init.d/mypushscript
update-rc.d mypushscript defaults
to make the script start at boot-time. I have not tested this so please do more research before making your own init script!
i want to run some command on several machine using ssh. I know it can be done by just using the command "ssh user#hostname command". However, the command i want to run print some string on the console. Is there any way that send all the strings back to the console that i'm on?
You could run the commands in a screen:
screen -S test
ssh user#hostname command1
ssh user#hostname2 command2
You can then detach (Ctrl-D) from the screen, let it run for however long it will run, then re-attach (screen -r test) to the screen and see all of the output. This assumes that you won't have a ton of output from the commands, however. Here's a link to a tutorial on screen.
ssh user#hostname command
Does just that. if 'command' outputs something, it'll show on the terminal you ran ssh from.
Try e.g. ssh user#hostname ls -l
But as others have said, GNU screen is invaluable for this type of work.
You probably want to use Gnu Screen for this. You can start a process in a "virtual" terminal, "detach" the terminal and log out for however long you want... Then you can ssh back in and re-attach the terminal to see the console output.
Also have a look at nohup, for example:
ssh user#domain.com nohup script_that_outputs_strings.py > the_strings.txt
Then if you want to go back and monitor the progress, you could check back and tail the file or scp the output back to your local machine.
Why don't you send you an email back?
Or use a log file, and scp it to your current computer?
otherwise, I don't know!