Ipcs do not show MODE

UNIX for Advanced & Expert Users
1

The ipcs -q command output includes a MODE column which tells user if the process is waiting on read or write on the queue. I used this in scripts on many systems (Solaris, AIX, SCO)

a snippet from man

 
MODE (all)
       The facility access modes and flags: The mode consists of
       11 characters that are interpreted as follows:
       The first two characters are:
     R
            if a process is waiting on a msgrcv;
     S
            if a process is waiting on a msgsnd;

output example

 
T     ID     KEY        MODE       OWNER    GROUP
Message Queues:
q      0 0x012a9fc2 -Rrw-rw-rw-     root     root

I run ipcs -q on Ubuntu 12.04 and the mode information is missing.

Is this peculiarity of Ubuntu, or all Linux distros are the same?

Note to administrators - I am not sure where to post this question, please move as you feel it best fit.

2

Try the command with following option.

ipcs -a

It supposed to show the output like following. Where perms is the numerical representation of modes.
777 is equivalent to RWXRWXRWX and
461 is equivalent to R_ _ RW_ _ _ X.

------ Shared Memory Segments --------
key             shmid       owner      perms      bytes      nattch     status
0x00000000 622604      alice        777        2804160    2           dest
0x00000000 61833230   bob         777        123840     2            dest
1 Like
3

Or

ipcs -qa

for message queues only