Self Destructing Bash Script

I want the script to run, exit terminal and then delete it's self.

Exit the terminal? I'm not sure what you're talking about here but maybe you need this (haven't tested it so not sure it works):

exit &

If you want the script to delete itself, this does the trick (assuming you have write permissions to the directory in which the script resides):

rm $0

N.B. This assumes that you are working in the same directory where the script is located.

Message was edited by: hungryjoe

Matt James1 wrote:

I know this is a pretty basic question, I am very new to shell scripting and I am looking for information on how to write a self destructing script. basically, I want the script to run, exit terminal and then delete it's self.

I think it would help if you gave more detail about what you want. For example, there's a difference between a script and a process. A script is a text document that contains some high-level commands in a given language (usually bash or tch for unix commands). A process is what you get when you run (execute) a script - the computer translates the text commands in the script file into low-level computer commands, and then creates and executes those commands. it's like the difference between a musical score (music written on paper) and the the same music played on instruments. most processes are self-terminating (unless they are built with endless loops of some sort), so nothing special normally needs to be done to 'delete' a process. scripts are text files, and you can delete them if you want, but that's not normal (since you usually want to run a script again at some point in the future).

Then it seems you want to use a launchctl command

man launchctl

first off, you don't put scripts in the LaunchDaemons folder. That folder is for plist files that get loaded as launchd jobs (where the jobs call scripts when triggered). I assume you know that, but you're not being very clear, so I need to make sure we're on the same page.

now, if you have a script that you only want to run after a disk is first imaged, you probably don't want to be using launchd at all. just store the script somewhere convenient, and have the disk imaging program run the script when it first mounts the disk after the imaging. if for some reason you feel the need to run the script via launchd, then have your script call launchctl to remove the launchd job from the list and disable the plist file (set its disabled key to true) so that it won't run again at reboot. deleting the plist (or the script) is unnecessary.

Message was edited by: twtwtw

I don't think that it's possible for a script to call launchctl to unload the daemons or launch agents which triggered it i.e. the parent process. One can however edit the plist files to set the disabled key as you say so that the daemon doesn't get loaded on the next reboot.

actually, it is possible (I've done it). of course, it stops the job that you're running, but if the unload command is the last line in the script that hardly matters.

Ah! So that's what I was doing wrong. I was trying to reload the launch agent (unload followed by load), but couldn't succeed. Is there a way of doing that without some kind of a workaround?

The reason you're having trouble here is that you're using the wrong method to accomplish your goal. launch agents and launch daemons are for tasks that occur every time particular conditions arise. Basically you've been asking "how do I launch this script every time the computer starts up, but stop doing it after the first time?", which is just silliness. Now I don't as a rule object to people trying to tighten a bolt with a hammer - not knowing any better and needing to improvise are good reasons to do that - but I don't see a reason to help you make the hammer work when there's a perfectly good wrench sitting on the table. Make the script executable and put it in /Library/StartupItems - then you can delete the script file from the process without any issues.

Well, actually my purpose was different from Matt's and cannot be solved with a startup script. I wanted my script to change the launch agent (like changing the StartInterval) if certain conditions changed — but of course then the launch agent has to be reloaded and there is no way of doing it with any script which is started by the launch agent itself.

hungryjoe wrote:
Well, actually my purpose was different from Matt's and cannot be solved with a startup script. I wanted my script to change the launch agent (like changing the StartInterval) if certain conditions changed — but of course then the launch agent has to be reloaded and there is no way of doing it with any script which is started by the launch agent itself.

if you want a launchd job to change under certain circumstances, that's easily accomplished by writing a second launch daemon that makes the changes. you just need to define the conditions correctly (and probably check in the script to make sure the process of the first job is not currently executing).