One thing lacking in traditional shell utilities is difficulty having a universally understood way of passing metadata about the content of the pipes/streams. Other commentators have (rightly!) pointed out the difficulties of requiring a single "structured object" in the core of the ecosystem... but if there were a way to gracefully support multiple structured object formats and let tooling build on top of that.
Got me wondering what would happen if we embedded modified form of HTTP response headers into the beginning of every UNIX command line stream. Let's tag this version `HTTP/UNIX.1`. This is to differentiate that this HTTP isn't due to a request, but as part of a standard 'UNIX' command response. Otherwise programs could follow RFC2616 section for HTTP response formats [1].
Speaking to the existing ecosystem of tooling, it'd be straightforward (trivial?) to add native support into existing shells to support this. For example now when you run `ls` your shell settings would be `SHELL_DISPLAY_HTTP_UNIX_PRETTY="terminal/text:terminal/json"`. Programs without native support built in could be handled by adding a "http_strip" program. Otherwise adding support into command line programs would be simple as libraries to handle HTTP/1.1 exist in most any language/platform and only a the "Response" header section would be needed of those. Alternately a generic wrapper could created to handle the http response info.
Examples:
HTTP/UNIX.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: ifconfig lo0
Content-Length: 248
Content-Type: terminal/text
Connection: Closed
lo0: flags=8049 mtu 16384
options=1203
inet 127.0.0.1 netmask 0xff000000
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
nd6 options=201
Next:
HTTP/UNIX.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: sysinfo
Content-Length: 107
Content-Type: terminal/json
Connection: Closed
{
"aggr0": {
"LACP mode": "active",
"Interfaces": [
"e1000g1",
"e1000g0"
]
}
}
Given this system could be in place, many tools could start adopting "json" or "messagepack" or other structured formats and generic tools could be built to translate in between formats. This is exacerbated now in that there's no way for programs to say "I'm outputting JSON" and "My json is using this json-schema://unix/some/random/filedescription/system". Or tools like `xargs` and `find` could attach header metadata of "Null-Terminator: \0" or "Null-Terminator: \n". Currently shell tools rely on command flags to set that, but if that feature flag could also be set by "Null-Terminator" header flags in the input/output streams it'd make the shell a lot more intuitive without reduce visibility. For example a common `find -print0 /etc | header_inspect` could be used to override shell settings and print out the header.
1: https://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html
edit: formatting whitespace?