Shell scripts & Startup

[DeletedAccount]

If i get a shell script to execute on startup via crontab.. will the script continue running until the next reboot? I am used to running a script for a java application in screen, which is starting to get annoying to have to re-open every restart.

 

Thanks 

[Nater]

I've never tried, but can't you just add it to the start up list? If for some messed up reason you can't just make a simple java script that starts it on start?

[RedWulf]

I'm not sure for cron, but as @Nater said theres more systematic ways to execute scripts at start up. But, assuming the cron job works the same as just adding the script to the "start up list" then it will only run once per boot. It will run once and end(unless you have a loop or restart or whatever) and will then run again upon restart. 

[DeletedAccount]

1 hour ago, RedWulf said:

I'm not sure for cron, but as @Nater said theres more systematic ways to execute scripts at start up. But, assuming the cron job works the same as just adding the script to the "start up list" then it will only run once per boot. It will run once and end(unless you have a loop or restart or whatever) and will then run again upon restart. 

One of my scripts starts a Proxy server, which i guess would continually run, and the other just starts a daemon, so i am guessing they could both be executed with cron? 

[Jonny]

Here is an example of a systemd service. Ubuntu 16.04 LTS uses systemd and so does Centos 7 (RHEL7)

 

 

create .service file in this example its "/lib/systemd/system/myscript.service"

[Unit]
Description=myscript
After=network.target

[Service]
User=bill
Group=bill
ExecStart=/home/bill/myscript.sh

[Install]
WantedBy=multi-user.target

 

now to enable the new service on startup we do

systemctl enable myscript.service

 

start the service and check its running

systemctl start myscript.service
systemctl status myscript.service

 

Arch Linux Wiki is pretty good for infomation, most files and commands are the same in Ubuntu and CentOS

https://wiki.archlinux.org/index.php/systemd

 

[DeletedAccount]

14 hours ago, Jonny said:

Here is an example of a systemd service. Ubuntu 16.04 LTS uses systemd and so does Centos 7 (RHEL7)

 

 

create .service file in this example its "/lib/systemd/system/myscript.service"

[Unit]
Description=myscript
After=network.target

[Service]
User=bill
Group=bill
ExecStart=/home/bill/myscript.sh

[Install]
WantedBy=multi-user.target

 

now to enable the new service on startup we do

systemctl enable myscript.service

 

start the service and check its running

systemctl start myscript.service
systemctl status myscript.service

 

Arch Linux Wiki is pretty good for infomation, most files and commands are the same in Ubuntu and CentOS

https://wiki.archlinux.org/index.php/systemd

 

Thanks, I will try it out later!

[gexacor]

If you need to run script at the startup you can use cron for that, and your application will work until the end or reboot the system.

 

But more convinient way to do that is writing the init.d script to launch your app at the system startup and stop it before the shutdown.

 

Take a look here for more related info, maybe it will help you.

[Jonny]

On 23/07/2016 at 9:01 AM, gexacor said:

If you need to run script at the startup you can use cron for that, and your application will work until the end or reboot the system.

 

But more convinient way to do that is writing the init.d script to launch your app at the system startup and stop it before the shutdown.

 

Take a look here for more related info, maybe it will help you.

You can do it that way but using a systemd service will be better. Better practice too.