I am relatively new to using ps. I cannot get ps to provide user-definend output in RHEL 6.2 using -o or o options. Simplest example, ps -o pid works in a BASH shell fiddlesh-4.2$ ps -o pid                                                                                                                                                                                                                               PID                                                                                                                                                                                                                                          19                                                                                                                                                                                                                                          29                                                                                                                                                                                                                                         But in the RHEL 6.2 VM I only get errors:[root@foobar ram]# ps -o pidERROR: Conflicting format options.********* simple selection *********  ********* selection by list *********-A all processes                      -C by command name<...more...>I've tried some other variations found online with no luck. Is there an issue with the particular syntax with RHEL 6.2? Would setting/changing the PS_PERSONALITY enviromental variable help?
ps user-defined output in RHEL 6.2
bash;rhel;ps