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How to ensure only one instance of a given script is running?
Closed 3 years ago. What is the simplest/best way to ensure only one instance of a given script is running – assuming it’s Bash on Linux? it doesn’t let me run the same script from separate accounts – which I would like sometimes. Of course, I can write my own pidfile handling, but I sense that there should be a simple way to do it.
How to schedule a script to run at start up?
In group policy editor you can add scripts to run at start up. The setting is under Computer Configuration/Windows Settings/Scripts/Startup. You could also use task scheduler to schedule the script to run at start up. Was this post helpful? Thanks for your feedback!
How to automatically run PowerShell scripts at a scheduled time?
Windows makes it possible to schedule PowerShell scripts to run at a predetermined time. The mechanism of choice for automating PowerShell scripts is the Windows Task Scheduler. The Windows Task Scheduler has been a part of the Windows operating system for many years.
Why do I need a separate control script?
Using a separate control script means that you can sanity check for edge cases: remove stale log files, verify that the lockfile is associated correctly with a currently running instance of the script, give an option to kill the running process, and so on. It also means you’ve got a better chance of using grep on ps output successfully.
How to make bash script run all the time?
Just curious how I can make a bash script run not only when I call it but all the time in the background. I have a bash script that is supposed to look for files and place them in the right folders, and I just want it so i don’t have to keep running that script manually.
What to do if the script is the same across all users?
If the script is the same across all users, you can use a lockfile approach. If you acquire the lock, proceed else show a message and exit. As an example: After /tmp/the.lock has been acquired your script will be the only one with access to execution.
How to make sure only one instance of a bash?
A solution that does not require additional tools would be prefered. Almost like nsg’s answer: use a lock directory. Directory creation is atomic under linux and unix and *BSD and a lot of other OSes.
What’s the best way to exit a shell script?
For shell scripts, I tend to go with the mkdir over flock as it makes the locks more portable. Either way, using set -e isn’t enough. That only exits the script if any command fails. Your locks will still be left behind.
How to create a read only file descriptor in Bash?
This is a modified version of Anselmo’s Answer. The idea is to create a read only file descriptor using the bash script itself and use flock to handle the lock.