How to find and print arguments of a command in ps?

Rather than formatting the output of ps and then using grep, you can simply use pgrep with -a option:

pgrep -a bash

This will show the command name (bash) along with its arguments (if any).

From man pgrep :

-a, --list-full
              List the full command line as well as the process ID.

Actually, you don't have to grep anything when using ps (at least the procps-ng implementation typically found on GNU/Linux systems, or the HP-UX ps), run this:

ps -o args= -C bash

If the list of arguments is very long, you may throw in a couple of -w options (though not on HP-UX):

ps -wwo args= -C bash