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?

Answer 1

This works on my Mac OS:

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

Answer 2

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.

Answer 3

In addition to bvamos's answer, according to the documentation the use of sem is deprecated :

NAME ipcrm - remove a message queue, semaphore set or shared memory id SYNOPSIS ipcrm [ -M key | -m id | -Q key | -q id | -S key | -s id ] ... deprecated usage

ipcrm [ shm | msg | sem ] id ...

remove shared memory

us ipcrm -m to remove a shared memory segment by the id

#!/bin/bash

set IPCS_M = ipcs -m | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

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

or ipcrm -M to remove a shared memory segment by the key

#!/bin/bash

set IPCS_M = ipcs -m | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

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

remove message queues

us ipcrm -q to remove a shared memory segment by the id

#!/bin/bash

set IPCS_Q = ipcs -q | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

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

or ipcrm -Q to remove a shared memory segment by the key

#!/bin/bash

set IPCS_Q = ipcs -q | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

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

remove semaphores

us ipcrm -s to remove a semaphore segment by the id

#!/bin/bash

set IPCS_S = ipcs -s | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f2 -d" "

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

or ipcrm -S to remove a semaphore segment by the key

#!/bin/bash

set IPCS_S = ipcs -s | egrep "0x[0-9a-f]+ [0-9]+" | grep $USERNAME | cut -f1 -d" "

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

Answer 4

This is how I do it in FreeBSD:

#!/usr/local/bin/bash
for i in $(ipcs -a | grep "^s" | awk '{ print $2 }');
do
        echo "ipcrm -s $i"
        ipcrm -s $i
done

Answer 5

to remove all shared memory segments on FreeBSD

#!/bin/sh
for i in $(ipcs -m | awk '{ print $2 }' | sed 1,2d);
do
    echo "ipcrm -m $i"
    ipcrm -m $i
done

to remove all semaphores

#!/bin/sh
for i in $(ipcs -s | awk '{ print $2 }' | sed 1,2d);
do
    echo "ipcrm -s $i"
    ipcrm -s $i
done

Answer 6

Since you mentioned that you're working on a NFS system, do you have access to those semaphores and shared memory? I think you misunderstood what they are, they are an API code that enables processes to communicate with each other, semaphores are a solution for preventing race conditions and for threads to communicate with each other, in simple answer, they do not leave any residue on any filesystem.

Unless you are using an socket or a pipe? Do you have the necessary permissions to remove them, why are they on an NFS system?

Hope this helps, Best regards, Tom.