One of the best ways to run scripts and instructions on droop and resume on Linux earlier than suspending (or after resuming) is to make use of the systemd init system. This is because of the truth that the init system interacts immediately with the kernel, and energy programs. Studying to work with this software will enable any person to achieve quite a lot of management over their Linux working system,
Please perceive that messing with the init system on your PC may be harmful for those who have no idea what you might be doing. Be sure you comply with the directions on this tutorial as intently as potential, to keep away from any potential mishaps.
Not each trendy Linux distribution helps the systemd init system. Some use upstart or one thing else solely. On this tutorial, we’ll focus on systemd as it’s the most typical initiation system. If you happen to’re seeking to accomplish this activity on one thing that doesn’t run what we cowl on this article, think about trying into your working system’s guide for directions.
Be aware: Debian customers ought to exchange all situations of usr/lib/systemd/system-sleep with /lib/systemd/system-sleep/
Working A Command Earlier than Suspend
To run a script earlier than droop, place any bash script file within the /usr/lib/systemd/system-sleep/ listing. The scripts themselves can do something, however there’s a sure syntax that have to be adhered to. Begin by opening up a terminal window. Utilizing sudo -s, achieve a root shell.
Subsequent, up the nano textual content editor contained in the system-sleep listing:
nano /usr/lib/systemd/system-sleep/pre-suspend.sh
Add the shebang to the beginning of the script. Including that is vital, and with out it, the interpreter won’t be able to accurately learn the code and instructions.
#!/bin/bash/
The following a part of the script is the “if”. This can inform the facility management system that “if” the system is about to go down for droop, one thing ought to occur. Paste the code under:
if [ "${1}" == "pre" ]; then
sh /path/to/script/to/run.sh
Change sh /path/to/script/to/run.sh within the script to no matter you’d wish to run on your Linux PC (or server) proper earlier than the system goes down for droop. Take into account that the road immediately after “if” doesn’t should be sh /path/to/script/to/run.sh. You may also use this to execute numerous instructions. So long as bash can acknowledge it as a command, it’s going to run.
The final a part of the “before suspend” script is so as to add the “else if” portion. This side of the script doesn’t should be modified, as, on this instance, we’re apprehensive about doing one thing earlier than the system goes down, and never when it wakes again up.
elif [ "${1}" == "post" ]; then
# nothing goes right here
fi
When all the things has been added to the file, press Ctrl + O to avoid wasting nano.
Working A Command After Resume
Executing a command after resume works very similar to operating one thing earlier than droop. The one actual distinction is as an alternative of including a command after the “if” portion of the script, you’d make a very powerful a part of the code happen after the “elif” line.
To make a post-resume script, first, add the shebang as the primary line.
#!bin/bash
On the subsequent line, add the “if” portion of the script.
if [ "${1}" == "pre" ]; then
# nothing goes right here
With that little bit of code pasted into the bash script, transfer down and paste the “else if” part.
elif [ "${1}" == "post" ]; then
sh /path/to/script/to/run.sh
fi
As soon as once more, it’s OK to put in writing something underneath the “elif” line. So long as it’s a regular command operation systemd and bash will run it.
Working Commands At Startup And Resume
If you happen to’d wish to run two reverse instructions; one earlier than droop, and one at resume, it’s potential. It simply means customizing the script and including strains underneath each the ‘if” line, in addition to the “elseif” line.
Like typical, begin out by posting the shebang into the script for the interpreter.
#!/bin/bash
Subsequent, paste the if part of the code.
if [ "${1}" == "pre" ]; then
# exchange with command
Underneath if, exchange “# replace with command” with no matter command you’d wish to run proper earlier than the system goes down. Then, transfer to the “elif” part, and do the identical.
elif [ "${1}" == "post" ]; then
# exchange with command
fi
Save the file with Ctrl + O,
Updating Permissions And Utilizing The Script
All the vital instructions are inside the script file, however earlier than it might probably run, you’ll must replace the permissions. Open up a terminal, and achieve root with: su or sudo -s. Then do:
chmod +x /usr/lib/systemd/system-sleep/pre-suspend.sh
From now on, everytime you droop or resume, customized instructions inside the script ought to run.
Be aware: have questions on systemd system-sleep? Test the guide with man systemd-suspend.service.
