Red Hat

You could alias ps into ps --cols ...

Even if we set COLUMNS=50 and then export it, any user can come around this restriction using ps -ww
Also, in unix, by default the output of ps command is curtailed to I think 70 chars and that does not go away even if you use ps -ww. But unix provides full output to the user who actually ran that particular command. Its just that other users can only see the curtailed output.
e.g if an user say albert ran a program having a long param chain. If albert himself runs ps command, he can see the full length of his command under ps list, but say another user jim runs the ps command, he can only see the curtailed output of the command (which albert had put to run). Even -ww option used by jim wont enable him to get the full command output.
Having said this, jim can see full output(more than 70 chars) of his programs under ps output list.

Are you attempting to stop other users from seeing sensitive things in ps listings? If so, curtailing ps won't stop them, there are other ways to obtain the commandline of a process.

Yes I agree, but the same stuff was smartly handled in Solarix, in which, they had truncated the output to 80 chrs. Thus all the sensitive info was cut off. So was wondering if that can be done in Linux.
Also, the use of columns env variable can not be a fool prof solution as its value can be changed. Even if we make it a readonly, its value can be changed in child processes and the readonly attribute does not hold true there.

Short answer: No.

Long answer: Obscurity is not security. ps is not a security tool. Even if you convinced ps to block the information, users could just get it direct from the source in /proc/####/comm.

Do you know for a fact that the first 80 chars never contains sensitive information, anyway? Commandline arguments were never a particularly safe place to put such things.

Funny on my solaris system with 130 char width and typing

Code:

 ps -ef |more

I have lines going to the end...

Even if it is so, if I get to truncate the ps command output to 80 chars for everyone(apart from process owner and root) then I will reach the goal.