CODEWITHSUNDEEP
linuxunixposixsemaphoreshared-memory
simone
simone

Reputation: 811

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

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

Upvotes: 39

Views: 116595

Answers (11)

mgttt
mgttt

Reputation: 361

#!/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

Upvotes: 10

pPanda_beta
pPanda_beta

Reputation: 648

1 line will do all

For message queue 

ipcs -q | sed "$ d; 1,2d" |  awk '{ print "Removing " $2; system("ipcrm -q " $2) }'

ipcs -q will give the records of message queues

sed "$ d; 1,2d " will remove last blank line ("$ d") and first two header lines ("1,2d")

awk will do the rest i.e. printing and removing using command "ipcrm -q" w.r.t. the value of column 2 (coz $2)

Upvotes: 2

riba
riba

Reputation: 326

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

Upvotes: 1

Mr_and_Mrs_D
Mr_and_Mrs_D

Reputation: 34026

Check if there is anything to delete with :

ipcs -a | grep `whoami`

On linux delete them all via :

ipcs | nawk -v u=`whoami` '/Shared/,/^$/{ if($6==0&&$3==u) print "ipcrm shm",$2,";"}/Semaphore/,/^$/{ if($3==u) print "ipcrm sem",$2,";"}' | /bin/sh

For sun it would be :

ipcs -a | nawk -v u=`whoami` '$5==u &&(($1=="m" && $9==0)||($1=="s")){print "ipcrm -"$1,$2,";"}' | /bin/sh

courtsesy of di.uoa.gr

Check again if all is ok

For deleting your sems/shared mem - supposing you are a user in a workstation with no admin rights

Upvotes: 2

RafaSashi
RafaSashi

Reputation: 17205

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

Upvotes: 0

John Moss
John Moss

Reputation: 11

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

Upvotes: 1

Serge
Serge

Reputation: 2006

This works on my Mac OS:

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

Upvotes: 11

neverMind
neverMind

Reputation: 1784

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

Upvotes: 67

bvamos
bvamos

Reputation: 772

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.

Upvotes: 10

t0mm13b
t0mm13b

Reputation: 34592

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.

Upvotes: 0

MBO
MBO

Reputation: 30995

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.

Upvotes: 7

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