ZOOKEEPER-5022: Added "exit" command to zkCli.sh

[PDavid]

as an alias for "quit" because that's a very common command to exit a shell.

[PDavid]

Testing

Built the project with mvn clean install -DskipTests
Set up config: cp conf/zoo_sample.cfg conf/zoo.cfg
Started ZooKeeper server: bin/zkServer.sh start
Started the ZK CLI: bin/zkCli.sh -server 127.0.0.1:2181

Then typed "exit" and pressed enter.

2026-03-06 15:06:25,232 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:java.library.path=/usr/java/packages/lib:/usr/lib64:/lib64:/lib:/usr/lib
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:java.io.tmpdir=/tmp
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:java.compiler=<NA>
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:os.name=Linux
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:os.arch=amd64
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:os.version=6.17.0-14-generic
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:user.name=david
2026-03-06 15:06:25,233 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:user.home=/home/david
2026-03-06 15:06:25,234 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:user.dir=/home/david/projects/upstream/zookeeper
2026-03-06 15:06:25,234 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:jvm.memory.free=232MB
2026-03-06 15:06:25,234 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:jvm.memory.max=256MB
2026-03-06 15:06:25,234 [myid:] - INFO  [main:o.a.z.Environment@98] - Client environment:jvm.memory.total=256MB
2026-03-06 15:06:25,235 [myid:] - INFO  [main:o.a.z.ZooKeeper@1123] - Initiating client connection, connectString=127.0.0.1:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@f8c1ddd
2026-03-06 15:06:25,241 [myid:] - INFO  [main:o.a.z.c.X509Util@85] - Setting -D jdk.tls.rejectClientInitiatedRenegotiation=true to disable client-initiated TLS renegotiation
2026-03-06 15:06:25,345 [myid:] - INFO  [main:o.a.z.c.X509Util@109] - Default TLS protocol is TLSv1.3, supported TLS protocols are [TLSv1.3, TLSv1.2, TLSv1.1, TLSv1, SSLv3, SSLv2Hello]
2026-03-06 15:06:25,347 [myid:] - INFO  [main:o.a.z.c.HostConnectionManager@127] - HostConnectionManager initialized with 1 servers
2026-03-06 15:06:25,349 [myid:] - INFO  [main:o.a.z.ClientCnxnSocket@235] - jute.maxbuffer value is 1048575 Bytes
2026-03-06 15:06:25,353 [myid:] - INFO  [main:o.a.z.ClientCnxn@1723] - zookeeper.request.timeout value is 0. feature enabled=false
Welcome to ZooKeeper!
JLine support is enabled
2026-03-06 15:06:25,357 [myid:127.0.0.1:2181] - INFO  [main-SendThread(127.0.0.1:2181):o.a.z.ClientCnxn$SendThread@1154] - Opening socket connection to server /127.0.0.1:2181.
2026-03-06 15:06:25,357 [myid:127.0.0.1:2181] - INFO  [main-SendThread(127.0.0.1:2181):o.a.z.ClientCnxn$SendThread@1156] - SASL config status: Will not attempt to authenticate using SASL (unknown error)
2026-03-06 15:06:25,365 [myid:127.0.0.1:2181] - INFO  [main-SendThread(127.0.0.1:2181):o.a.z.ClientCnxn$SendThread@1007] - Socket connection established, initiating session, client: /127.0.0.1:44440, server: /127.0.0.1:2181
2026-03-06 15:06:25,373 [myid:127.0.0.1:2181] - INFO  [main-SendThread(127.0.0.1:2181):o.a.z.ClientCnxn$SendThread@1427] - Session establishment complete on server /127.0.0.1:2181, session id = 0x100139a92070024, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null zxid: -1
[zk: 127.0.0.1:2181(CONNECTED) 0] exit

WATCHER::

WatchedEvent state:Closed type:None path:null zxid: -1
2026-03-06 15:06:28,129 [myid:] - INFO  [main-EventThread:o.a.z.ClientCnxn$EventThread@581] - EventThread shut down for session: 0x100139a92070024
2026-03-06 15:06:28,130 [myid:] - INFO  [main:o.a.z.ZooKeeper@1339] - Session: 0x100139a92070024 closed
2026-03-06 15:06:28,133 [myid:] - INFO  [main:o.a.z.u.ServiceUtils@45] - Exiting JVM with code 0
$

[anmolnar]

lgtm.

[PDavid]

org.apache.zookeeper.server.DatadirCleanupManagerTest.testPurgeTask test failed in the PR build. I think it is unrelated to the changes of this PR.