Complete all of the necessary and basic commands first

[dtg-lucifer]

🔌 Server & Connection

• PING – Check if server is alive
  Usage: PING → PONG
• ECHO <message> – Return the message
  Usage: ECHO "Hello" → "Hello"
• SELECT <index> – Switch to DB index
  Usage: SELECT 1
• FLUSHDB / FLUSHALL – Clear keys in DB or all DBs
  Usage: FLUSHDB, FLUSHALL
• DBSIZE – Get number of keys in current DB
  Usage: DBSIZE → 3

🧠 Strings

• SET <key> <value> / GET <key>
  Usage: SET name Alice, GET name → Alice
• DEL <key> – Delete key
  Usage: DEL name → 1
• EXISTS <key> – Check if key exists
  Usage: EXISTS name → 0
• INCR <key> / DECR <key>
  Usage: SET counter 10, INCR counter → 11, DECR counter → 10
• APPEND <key> <value> – Append to string
  Usage: APPEND name " Smith" → 11
• GETSET <key> <value> – Set new value, return old
  Usage: GETSET name Bob → Alice
• MSET key1 val1 key2 val2 ... – Set multiple keys
  Usage: MSET a 1 b 2

🔑 Key Management

• KEYS <pattern> – Match keys with glob pattern
  Usage: KEYS * → [a, b, name]
• TYPE <key> – Get value type
  Usage: TYPE name → string
• EXPIRE <key> <seconds> – Set TTL
  Usage: EXPIRE name 10
• TTL <key> – Time to live
  Usage: TTL name → 9
• PERSIST <key> – Remove expiration
  Usage: PERSIST name

📃 Lists

• LPUSH <key> <value> / RPUSH <key> <value>
  Usage: LPUSH fruits apple, RPUSH fruits banana
• LPOP <key> / RPOP <key>
  Usage: LPOP fruits → apple
• LRANGE <key> <start> <stop> – Get sublist
  Usage: LRANGE fruits 0 -1 → [banana]
• LLEN <key> – Length of list
  Usage: LLEN fruits → 1

📦 Sets

• SADD <key> <member> – Add to set
  Usage: SADD tags red
• SREM <key> <member> – Remove from set
  Usage: SREM tags red
• SISMEMBER <key> <member> – Check membership
  Usage: SISMEMBER tags blue → 0
• SMEMBERS <key> – List all members
  Usage: SMEMBERS tags → [blue, green]
• SCARD <key> – Count members
  Usage: SCARD tags → 2

🧾 Hashes

• HSET <key> <field> <value> – Set field
  Usage: HSET user name Alice
• HGET <key> <field> – Get field
  Usage: HGET user name → Alice
• HDEL <key> <field> – Delete field
  Usage: HDEL user name
• HGETALL <key> – Get all field-value pairs
  Usage: HGETALL user → [name, Alice, age, 25]
• HLEN <key> – Count fields
  Usage: HLEN user → 2

📊 (Optional) Sorted Sets (ZSets)

• ZADD <key> <score> <member> – Add with score
  Usage: ZADD scores 100 Alice
• ZRANGE <key> <start> <stop> [WITHSCORES]
  Usage: ZRANGE scores 0 -1 WITHSCORES → [Alice, 100]
• ZREM <key> <member> – Remove member
  Usage: ZREM scores Alice
• ZCARD <key> – Count members
  Usage: ZCARD scores → 0

🧪 Testing & Debug

• Add basic REPL to accept input commands
• Add command logging for debugging
• Add unit tests for each data type and command