Delete all SYSTEM V shared memory and semaphores on UNIX-like systems

Question

How can I delete all not used semaphores and shared memory with a single command on a UNIX-like system, e.g., Ubuntu?

Solution 1

Here, save and try this script (kill_ipcs.sh) on your shell:

#!/bin/bash

ME=`whoami`

IPCS_S=`ipcs -s | egrep "0x[0-9a-f]+ [0-9]+" | grep $ME | cut -f2 -d" "`
IPCS_M=`ipcs -m | egrep "0x[0-9a-f]+ [0-9]+" | grep $ME | cut -f2 -d" "`
IPCS_Q=`ipcs -q | egrep "0x[0-9a-f]+ [0-9]+" | grep $ME | cut -f2 -d" "`


for id in $IPCS_M; do
  ipcrm -m $id;
done

for id in $IPCS_S; do
  ipcrm -s $id;
done

for id in $IPCS_Q; do
  ipcrm -q $id;
done

We use it whenever we run IPCS programs in the university student server. Some people don't always cleanup so...it's needed :P

Solution 2

This works on my Mac OS:

for n in `ipcs -b -m | egrep ^m | awk '{ print $2; }'`; do ipcrm -m $n; done

Solution 3

ipcs -s | grep $USERNAME | perl -e 'while (<STDIN>) { @a=split(/\s+/); print `ipcrm sem $a[1]`}'

or

ipcs -s | grep $USERNAME | awk ' { print $2 } ' | xargs ipcrm sem

Change $USERNAME to a real username.

Solution 4

#!/bin/bash
ipcs -m | grep `whoami` | awk '{ print $2 }' | xargs -n1 ipcrm -m
ipcs -s | grep `whoami` | awk '{ print $2 }' | xargs -n1 ipcrm -s
ipcs -q | grep `whoami` | awk '{ print $2 }' | xargs -n1 ipcrm -q

Solution 5

I don't know how to delete all at once, but you can use ipcs to list resources, and then use loop and delete with ipcrm. This should work, but it needs a little work. I remember that I made it work once in class.

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Comments

[simone]

no this doesn't help me...i'm just doing a simple c project for a fake nfs...i know what are semaphores and shared memory...i just want to do some test on my code and i need to remove all the shared data in one click

[t0mm13b]

@simone: You should have stated 'fake nfs' on your original question and pointed out that you understood semaphores and shared memory... it is still not clear as to what is "shared data"?

[t0mm13b]

And also inclusion of code as well to show your homework for us SO'ers to see....that would be of help also...

[Duck]

Do we know if he is using SysV ipc and not POSIX?

[MBO]

@Duck We know he's using Ubuntu, and I checked those commands on Ubuntu

[Duck]

Right but ipcs only works with SysV ipc objects. If he is using the posix versions they will show in /dev/shm where he can just rm them.

[Burkhard]

Thanks. Exactly what I was looking for.

[Ben]

Doesn't that delete all of them, even if nattach is nonzero? What about this?: ipcs -m | egrep "0x[0-9a-f]+ [0-9]+"|awk '{ if ($6 == 0) { print $2; } }'|xargs -n1 ipcrm -m

[user1202136]

I would replace the for loops with xargs: echo $IPCS_S | xargs -n1 ipcrm -s.

[brainydexter]

For me the above regex didn't work. The following did IPCS_Q=ipcs -q | egrep -i "0x[0-9a-f]+.*[0-9]+" | grep $ME | cut -f2 -d" "``

[LeoPucciBr]

On AIx systems does not work either.. some minor tweaks on the commands did the trick! ipcs -s |grep $ME | awk '{print $2}' The awk command solves the positioning problems.

[Oleg Oleg]

It's a great answer, it helped me to remove queues with key 0x0 (which cannot be removed using ipcrm -Q option)