SEP: Unifying Sage's command line interface

This SEP proposes to come up with a new command line interface that is more in line with getopt.

Proposal

Sage should use the standard getopt way for its options. http://www.systhread.net/texts/200704optparse.php In particular long options must start with two dashes instead of the current practice just one or two. This is in line with http://trac.sagemath.org/sage_trac/ticket/21.

In addition to that, Sage might change its command line interface in such a way that it looks more like that of modern source code management systems (e.g., Mercurial). For example,

sage hg

would start Mercurial. Any additional arguments would be passed to hg. Other example.

sage gap

would start gap. As an exception sage would start the Sage session itself.

Similar to hg, sage help would list of all available commands. Furthermore sage help COMMAND would return an appropriate help for all the options that correspond to COMMAND. Such a system would be pluggable, since it does not need to hardcode all help text in a central place. Rather the help text for a command should be produced by the respective script. (Currently there is already an infrastructure of the sage-* scripts.

Developer commands should be separated from user commands.

Sage commands and their options

The following lists are not yet fleshed out completely. But before any implementation should happen, there should be an agreement on the interface.

User commands

(no command)

-v --version

Print version information.

help

Overview of all available commands.

gap

ditto

singular

ditto

spkg

Sage package handling (similar to Debian's dpkg or apt-get). That should install appropriate binaries for the respective machine.
make should not be necessary on the user's machine.

run

Run the given file. (??? Shouldn't sage < file.sage >result.out do the same?

upgrade

Upgrade to a new version of Sage.

Developer commands

hg: should be identical to calling Mercurial directly.
gdb: Run sage controlled by gdb.

Superfluous commands (because they are done via 'make')

The command sage should run Sage and not be misused for development processes. The make tool should deal with building Sage and its documentation