I definitely agree with you, Tux, using the output of a ps shell command is usually not a good idea, and I was on the verge of writing just that in my previous post, but I refrained from doing it, because it seems that the OP is really reading from a large file with the output of the ps command, so that it appears to be perhaps a one-off task on an existing file containing historical trace of what happened on a Linux box sometimes ago (a kind of post-mortem analysis).