Strings

The most fundamental data type in Lux. Strings can hold any binary data up to 512MB, including text, serialized JSON, or raw bytes. They also support atomic integer and float operations.

SET / GET

Set a key to a string value and retrieve it. SET supports optional expiration and conditional flags.

SET key value [EX seconds | PX milliseconds] [NX | XX]
GET key

> SET user:1 "alice" EX 3600
OK
> GET user:1
"alice"
> SET lock:checkout "held" NX
OK
> SET lock:checkout "other" NX
(nil)

SETNX / SETEX / PSETEX

SETNX sets a key only if it does not exist. SETEX and PSETEX set a value with an expiration in seconds or milliseconds.

SETNX key value
SETEX key seconds value
PSETEX key milliseconds value

> SETNX session:abc "data"
(integer) 1
> SETEX cache:page 300 "<html>..."
OK
> PSETEX temp:token 1500 "xyz"
OK

MGET / MSET / MSETNX

Batch get or set multiple keys in a single round trip. MSETNX only sets all keys if none of them exist.

MSET key value [key value ...]
MGET key [key ...]
MSETNX key value [key value ...]

> MSET name "alice" age "30" city "nyc"
OK
> MGET name age city
1) "alice"
2) "30"
3) "nyc"

GETSET / GETDEL / GETEX

Atomic read-and-modify operations. GETSET replaces a value and returns the old one. GETDEL returns and deletes. GETEX returns the value and optionally sets a new expiration.

> SET counter "10"
OK
> GETSET counter "0"
"10"
> GETDEL temp:job
"payload-data"
> GETEX session:x EX 600
"active"

INCR / DECR / INCRBY / DECRBY / INCRBYFLOAT

Atomic numeric operations on string values. The value must be parseable as an integer (or float for INCRBYFLOAT).

> SET hits 100
OK
> INCR hits
(integer) 101
> INCRBY hits 50
(integer) 151
> DECRBY hits 10
(integer) 141
> INCRBYFLOAT price 2.5
"142.5"

APPEND / STRLEN / GETRANGE / SETRANGE

String manipulation. APPEND concatenates to an existing value. STRLEN returns the length. GETRANGE and SETRANGE operate on substrings by byte offset.

> SET greeting "Hello"
OK
> APPEND greeting " World"
(integer) 11
> STRLEN greeting
(integer) 11
> GETRANGE greeting 0 4
"Hello"
> SETRANGE greeting 6 "Lux!!"
(integer) 11
> GET greeting
"Hello Lux!!"

Command Reference

Command	Description
SET	Set a key to a value with optional expiration and flags
GET	Get the value of a key
SETNX	Set key only if it does not exist
SETEX	Set key with expiration in seconds
PSETEX	Set key with expiration in milliseconds
GETSET	Set key and return the previous value
GETDEL	Get the value and delete the key
GETEX	Get the value and optionally set expiration
MGET	Get values of multiple keys
MSET	Set multiple key-value pairs
MSETNX	Set multiple keys only if none exist
STRLEN	Get the length of the string value
APPEND	Append a value to an existing string
INCR	Increment integer value by 1
DECR	Decrement integer value by 1
INCRBY	Increment integer value by a given amount
DECRBY	Decrement integer value by a given amount
INCRBYFLOAT	Increment float value by a given amount
GETRANGE	Get a substring by byte offsets
SETRANGE	Overwrite part of a string at a byte offset

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