Hi,
We have a AIX 5.3 box. The 'who' command is not displaying the users loggged in to the system. Even who -a doesnt list out all the users. What are the details that I need to provide? Could it be a permission issue? Slightly confused at this moment.

The who -q gives output as '0 users'. Very strange!!

I do not know that much AIX. Do you have a utmp or utmpx file that show activity - ie. get larger over time?

Normally these files are maintained by init, login, getty, telnet; entries are constantly being added on an active system.

The utmp file is getting updated. Even the /var/adm/wtmp file gets updated. I check the ouput of 'last' and some of the rows show that system was halted abnormally. Could this be the cause of the issue? Sometimes, the last 's output shows a terminal itself as a user. Please find a sample output.
I also cannot understand how the above line(in bold red) appears. Has the file got corrupted?

Not necessarily - it just means init did not cleanup when the process ended.
Does AIX have the equivalent of truss, tusc or strace?

Try AIX's equivalent of to find out if there are permissions problems. Truss/strace and some other utilities show all system calls and their result.

hai,

I have been working in AIX 5.1 version. and in that who command is working fine. Even who -a and who -q is giveing list of users corrently logged into the system.
you can try out following option with who command :
-A
Displays all accounting entries in the /etc/utmp file. These
entries are generated through the acctwtmp command.
-m
Displays information about the current terminal only. The who -m
command is equivalent to the who am i and who am I commands.

even though if its not working then it might be the issue of permissions/rights given to you.

thanks.