Querying .ics files, SSH authorized_keys, and more with jq

I maintain [jc](https://github.com/kellyjonbrazil/jc), a tool that converts the output of CLI commands and file types to JSON so you can query them with `jq`. A few recent parsers cover files I used to fight with `grep` and `awk`, so I wrote up some examples. Here are a few highlights:

**What's on the calendar today?**

cat work.ics | jc --ics | jq -r '.[] | select(.dtstart | startswith("2026-10-19")) | .summary'

Timestamps are normalized to ISO 8601, `mailto:` prefixes are stripped, and attendees come out as an array with name, role, and RSVP status.

**Which SSH keys have no `from=` or `command=` restriction?**

cat ~/.ssh/authorized_keys | jc --authorized-keys | jq -r '.[] | select(any(.options[]; startswith("from=") or startswith("command=")) | not) | .comment // "(no comment)"'

Options are split into an array, and quoted values like `command="/usr/bin/rsync --server ..."` stay intact.

**CSV with no header row?**

cat access.csv | jc --csv-ih | jq -r '.[] | select((.c2 | tonumber) >= 500) | .c4'

Columns are named `c0`, `c1`, and so on. The post includes a `jq` one-liner to swap in your own names. There are also `--tsv`, `--tsv-ih`, and streaming versions (`-s`) that output JSON Lines for huge files.

Full write-up with more examples: [JC Tips and Tricks – Part 3](https://blog.kellybrazil.com/2026/10/19/jc-tips-and-tricks-part-3/)

I'd love to hear what file formats you still parse by hand. That's usually where the next parser comes from.