The language

proton <app> <collection> <verb> [TARGET…] [--flags]

proton mail messages list
proton drive items move /report.pdf --into /Archive
proton pass items get github.com
proton calendar events create --title Standup --start 2026-04-16T09:00

A group never does anything itself - proton mail settings prints help, proton mail settings get shows your settings. Every command that acts is named by a verb.

Verbs

One word per idea, everywhere it appears.

Verb	Means
list · get	show a collection, or one thing in full
create · update · delete	the usual three
trash · restore · empty	remove reversibly, put back, clear out
move --into · copy --into	put into another container
upload · download	move bytes to or from your disk
export · import	documents to or from disk
send · reply · forward	mail going out
label · unlabel · star · unstar	attach or detach
enable · disable	turn a thing on or off
add · remove	put a member into a container, or take one out
accept · decline	answer an invitation
set	write one setting
login · logout	your session

To rename anything, use update --name. The command reference has the full list.

Saying which ones

Every command that can act on many things takes the same two ways of saying which: name them, or describe them. Both at once is a union.

proton mail messages trash 5bH2mQxK 9xL4pQrT
proton mail messages trash --from newsletter@example.com --older-than 90d
proton mail messages trash 5bH2mQxK --unread --folder spam

Filter	Means
--folder · --scope · --vault	where to look
--older-than · --newer-than	by age
--larger-than · --smaller-than	by size
--pattern	match the name against a glob
--unread · --starred · --type	by state or kind
--all	everything in scope, rather than a subset
--limit	cap how many a bulk verb affects

list takes the same filters as the verbs beside it, so you can see a selection before acting on it:

proton drive items list /Build --pattern "*.tmp" --recursive   # see what matches
proton drive items trash --scope /Build --pattern "*.tmp" --recursive

What list says with its PATH argument, a bulk verb says with --scope, because it uses its arguments to name things instead.

A command needs at least one reference or filter:

$ proton mail messages trash
Error: Nothing selected.
Try:   pass a REF, or a filter such as --unread, --starred, --from or --older-than.
       Use --all to target a whole folder.

When it asks first

proton asks before it removes something it cannot put back, and before it removes things you did not name. Nothing else ever stops to ask.

	you named it	a filter found it
delete · empty · uninstall	asks	asks
trash	just does it	asks
everything else	just does it	just does it

The question shows the things themselves, never a count:

$ proton mail messages delete --from newsletter@example.com --older-than 90d
Would delete 3 messages:

ID        FROM          SUBJECT              DATE
────────  ────────────  ───────────────────  ────────────────
hR8sT2vW  Example News  January round-up     2026-01-08 06:00
kM4nP9qL  Example News  December round-up    2025-12-08 06:00
zC7bX1yE  Example News  November round-up    2025-11-08 06:00

This cannot be undone. Continue? [y/N]

Anything but a plain y means no, including pressing enter. (Why these two cases.)

In a script there is nobody to ask, so the question becomes an error and nothing is removed. --yes is the answer given in advance:

$ proton mail messages delete --folder spam --older-than 30d
Error: Would delete 112 messages. This cannot be undone.
Try:   --yes to confirm, or --dry-run to see what it would touch.

Dry runs

Every command that changes something takes --dry-run. It resolves references, applies filters, and shows you the things themselves:

$ proton mail messages trash --from newsletter@example.com --older-than 90d --dry-run
Dry run - would move 3 messages to trash:

ID        FROM          SUBJECT              DATE
────────  ────────────  ───────────────────  ────────────────
hR8sT2vW  Example News  January round-up     2026-01-08 06:00
kM4nP9qL  Example News  December round-up    2025-12-08 06:00
zC7bX1yE  Example News  November round-up    2025-11-08 06:00

Dry-run output goes to stderr, so it still appears if you redirect stdout.

Getting help

Every command documents itself, and completion knows the whole tree - including which values each constrained flag accepts.

proton --help
proton mail messages send --help

Next: naming the thing you want, and what comes back.