Implement time

[GrayJack]

This is a tracking issue for the time utility.

Required options and flags in the POSIX standard:

• p (long: posix, alias: portability)

Required extension options and flags:

• l (long: rusage)
• o (long: output)
• a (long: append, requires: o)

Notes:
¹ : Long name not defined on other implementation of this utility. Implementer must choose a long name.
² : Short name (one letter) not defined on other implementation of this utility. Implementer must choose. a short name

References

POSIX standard text
FreeBSD Manual
NetBSD Manual
OpenBSD Manual
DragonFlyBSD Manual

Unresolved questions:

Each time implementation has some unique extensions. One may need one of those in their respective system.

History

p flag/option implemented in #141

[envp]

Posting TODO here from #141:

Compatibility so far for time.1:

• POSIX.2
• MacOS
• Linux WITHOUT GNU extensions
• Linux GNU extensions
• FreeBSD
• NetBSD
• OpenBSD
• DragonflyBSD
• Illumos
• Solaris
• Fuchsia: No getrusage syscall

[envp]

#144 adds features from BSD time commands. -l is still unimplemented, as that requires some more work on macos (discussed on the PR)