tail(1): Add some long options

[kevans]

Summary

Add --blocks, --bytes, and --lines long options for -b, -c, and -n respectively. This improves tail(1)'s compatibility with its GNU counterpart in a straightforward way.

[eadler]

tail/tail.c

67 ↗

(On Diff #38699)

don't forget to update usage too

[imp]

love the idea of this, couple of minor quibbles.

tail/tail.1

76 ↗

(On Diff #38699)

elsewhere this is Fl -blocks, a custom I've continued. I'd hold off committing until Warren gives this the nod. Likely worth a one-liner in style(9).

tail/tail.c

67 ↗

(On Diff #38699)

usage not updated.

[kevans]

tail/tail.1

76 ↗

(On Diff #38699)

For what it's worth, I copied this convention from grep(1), so I wasn't trying to go completely off the reservation. We should probably make a pass and address a lot of this so we're consistent.

tail/tail.c

67 ↗

(On Diff #38699)

I didn't update usage because we don't tend to document long option alternatives to existing flags, from what I can tell. I use both sed and grep here as examples.

[bjk]

tail/tail.1

76 ↗

(On Diff #38699)

If we're taking a poll, I'm used to `.Fl -blocks``` for long options.

[kevans]

Switch to Fl -longopt instead of Fl Fl longopt; the former looks cleaner and is a much nicer convention

I've still left these out of usage for the time being, because I'm still not entirely sure it needs updated- I'm still (slightly) searching for an example where we actually document the long option alternative to a short option in usage. Everything I've found so far never documents both in usage, and it prefers the short option when possible.

[kevans]

Committed, but Phabricator won't give me the option to just close it.