Understanding NDCTerm Command Grammar

The first character is the namespace

NDCTerm's entire language is one pattern: prefix, target, body, qualifiers. The prefix — the first character — tells you the command family. Learn the fourteen prefixes and you can classify any command before you've read the rest of it.

Two of these deserve a note before anything else:

• No prefix means search. A line that starts with a date is a search: 15NOVJFKLAX. Always lead with the DDMMM date — Getting Started explains why a bare city pair is a trap.
• X is a prefix, never a command. X1 deletes segment 1, XA deletes all segments, XP1 deletes passenger 1 — but a bare X is rejected by the parser, so a stray keystroke can't wipe your work. To reset the transaction, use I or CLEAR.

Targeting: P for passenger, S for segment

Inside a command, P<n> names a passenger and S<n> names a segment, both 1-indexed by their position in the transaction sidebar or order display. Targets slot in right after the prefix, most specific last:

@DOB01JAN1980      # No target — applies to the LAST passenger added
@P2/DOB15MAR1985   # Explicit target — passenger 2
$P1/12A            # Seat 12A for passenger 1
!P1/VGML           # Vegetarian meal for P1, every segment
!P1/S2/WCHR        # Wheelchair for P1, segment 2 only — P and S compose
%P1/UA/123456789   # Loyalty number for P1's whole itinerary

The default rule is consistent: omit the passenger target and the command applies to the last passenger added — with one deliberate exception. SSRs (!) always require an explicit P<n>; a special-service request never guesses its passenger.

Qualifiers chain with /

Everything after the body of a command chains with /, and within a family the order is mostly free — search modifiers in particular can appear in any order:

15NOVJFKLAX/SHOP/J/2ADT/1CHD  # Live-priced, business cabin, 2 adults + 1 child
15NOVJFKLAX/SHOP7/AA          # Same meaning as 15NOVJFKLAX/AA/SHOP7

Read a chained command left to right: body first, then each / token narrows or annotates it. Every qualifier belongs to one axis (carrier, cabin, passenger mix, connection rule, …); you'll never see two axes share a token.

Ranges and sets

Wherever a command takes numbers, two separators work, and they work identically across every family — selection, deletion, issuance:

• - is a range: 1-5 means 1 through 5.
• / is a set: 1/3 means 1 and 3, nothing between.

1-5                # Select rows 1 through 5
1/2/3              # Select rows 1, 2, and 3
X1-3               # Delete segments 1 through 3
ISSUE/1/3          # Issue cart items 1 and 3 only

The commit verbs: ER, E, ET, ETR

Four verbs end a transaction, and they compose from two letters: E ends (commits), T tickets, R retrieves (displays the result):

• ER — commit and display the order. The default reflex.
• E — commit silently, no display.
• ET — commit and issue documents, no display.
• ETR — commit, issue, and display: booking to ticket in one call.

They appear two ways. Suffixed to a priced-offer row, they commit that offer: 1ER books a new offer on hold or accepts an exchange on hold where supported; 2ETR books or exchanges offer 2 and tickets it immediately. Some exchanges cannot be held, so ER directs you to the payment-backed ETR flow without committing. Standalone, the verbs commit whatever is queued in the transaction — queued seat assignments and other order changes — so a post-booking seat pick is $P1/12A then ER. Ticketing verbs need payment in place first; that whole topic is Issue and Verify Tickets.

Parsing an unfamiliar command

Put the pieces together and unfamiliar commands read themselves. Cover the answer and decompose these:

+P1/BAG1/25KG      # + ancillary · P1 · one bag · 25kg
X1/2/3             # X delete · segments 1, 2, and 3 (set, not range)
*-SMITH/JOHN       # * lookup · - by passenger name · SMITH/JOHN
$P1/X              # $ seats · P1 · /X removes — the delete prefix reused as a suffix
D1                 # D split · passenger 1 into a new order

That last pattern is worth internalizing: /X as a trailing qualifier means remove — $P1/X drops P1's seat — while X as a leading prefix deletes by number. Same letter, position decides.

Where to look things up

• The command reference is the complete lookup table, organized by the same families as the prefix table above. Keep it open in a second tab.
• Inside the terminal, ? answers questions about the current transaction: ?FR fare rules, ?BAG baggage allowance for the offer in front of you.
• Per-airline support for specific operations varies — check the carrier's page under Airlines.

Next: put the grammar to work — Search for Flights.