- Change `-p' to allow a list of process IDs, and `-t' to allow a list
of terminal names, instead of only a single value for each.
- Add the `-A' option of SUSv3, which is exactly the same as `-ax'.
- Add the `-G gidlist' (group id).
- Allow any of these "selector options" to be specified multiple times,
and have `ps' keep adding to a given list -- instead of replacing the
previously-specified values.
- Fix interactions between selector-options, so that: "If any are
specified, ... ps shall select the processes represented by the
inclusive OR of all the selection-criteria options." (from SUSv3)
- Add a `-X' option, which is the reverse of the `-x' option.
- various minor improvements in parsing and error handling.
This does not get us to match POSIX/SUSv3, but it gets us closer. The
`-g pgidlist', `-R ruserlist' and `-s sidlist' options mentioned in
freebsd-standards are still under debate, so they skipped for now.
It should be true that this introduces no user-visible incompatible
changes, except to support "new stuff" that was not supported before.
2b815e77ed