There is a -t for table format and --json for JSON format, both of which are scriptable, if somewhat annoying depending on the tools you use/familiarity with sed/awk.

We definitely do need better tooling, but I think it needs some thought behind it so we don't keep hacking together scripts.

I've taken a lifelong vow never to learn sed/awk, and dealing with JSON is really a hassle if it can be avoided (thought that's the route I went in my most recent barbarism).

Yes we need better tools, but I don't think added a "--host" option falls into the back-to-the-drawing-board category.

True.  I am a little concerned because I don't think anyone will vouch that atest server list accurately reflects, e.g., the list of prod shards.

 -N, --hostnames-only 
Let's use the same option for atest host list.

Re #3, atest server list must matches the list of prod shards. If there is a mismatch, the shard could be skipped for push to prod. We might consider something to enforce the two lists match.

Agreed with #4

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/e1729bb1558c8070c2459a310e59aa2320f4a0d3

commit e1729bb1558c8070c2459a310e59aa2320f4a0d3
Author: Aviv Keshet <akeshet@chromium.org>
Date: Thu Jun 01 04:14:38 2017

autotest: add `atest server list -N` option to list only hostnames

BUG= chromium:721591 
TEST=atest server list -N

Change-Id: Ia3a3cbecc901b8dc58e59d41bbf5057bb5396b00
Reviewed-on: https://chromium-review.googlesource.com/520122
Commit-Ready: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Dan Shi <dshi@google.com>

[modify] https://crrev.com/e1729bb1558c8070c2459a310e59aa2320f4a0d3/site_utils/server_manager_utils.py
[modify] https://crrev.com/e1729bb1558c8070c2459a310e59aa2320f4a0d3/cli/server.py