So, what can you do with a process ID? • Hacker News Board

Re: So, what can you do with a process ID?

#21

Post by jasonhansel » Sat, Dec 17, 2022, 5:28 PM UTC

hsfzxjy wrote: post #3

And with strace -p pid you can somewhat "spy" on what a process is doing.

`lsof -p pid` can also be a good way of determining what a process is doing at a given point in time, if you're just trying to figure out what files it has open.

Re: So, what can you do with a process ID?

#22

Post by ktpsns » Sat, Dec 17, 2022, 5:48 PM UTC

Another nice addition would have been debuggers such as gdb -p PID to hook into the running code, see for instance https://stackoverflow.com/questions/2308653/can-i-use-gdb-to...

Re: So, what can you do with a process ID?

#23

Post by nealabq » Sat, Dec 17, 2022, 6:05 PM UTC

kmstout wrote: post #14

Way hay we're out of memory Way hay our disk is thrashing Way hay I need more coffee Early in the morning! What can you do with a process ID What can you do with a process ID What can you do with a process ID Early in the morning? Send a SIGKILL to its process Send a SIGKILL to its process Send a SIGKILL to its process Early in the morning!

But what do you do with a zombie process? I haven't found the lyrics that tell me.

https://en.wikipedia.org/wiki/Drunken_Sailor

Re: So, what can you do with a process ID?

#24

Post by zbentley » Sat, Dec 17, 2022, 8:10 PM UTC

tdoot wrote: post #2

Interesting there's no mention of the /proc filesystem ( https://docs.kernel.org/filesystems/proc.html ). cat /proc/ /environ would be a solid addition to this list.

True, but as written it has advice applicable to non-linux environments like MacOS, which don't have /proc.

Re: So, what can you do with a process ID?

#25

Post by pletnes » Sun, Dec 18, 2022, 1:53 PM UTC

rwmj wrote: post #16

pletnes wrote: post #15

I know about some of these tricks. However, containers are popular and typically don’t have the tools installed, and you can’t necessarily sudo either. What do people replace these tricks with, in some cloud container or k8s pods?

If /proc is mounted in the container you can grab the same information (more tediously) by looking at /proc/

Some things are there, but real tedious, yes. I haven’t found something convenient and if you’re not root, some of the useful things are inaccessible.

Re: So, what can you do with a process ID?

#26

Post by rwmj » Sun, Dec 18, 2022, 3:25 PM UTC

pletnes wrote: post #25

rwmj wrote: post #16

Earlier quoted context omitted.

If /proc is mounted in the container you can grab the same information (more tediously) by looking at /proc/

Some things are there, but real tedious, yes. I haven’t found something convenient and if you’re not root, some of the useful things are inaccessible.

Could you copy in (or sideload) a statically linked "top" binary?