config interface 'gm'
        option ifname 'eth0.2'
        option proto 'static'
        option netmask '255.255.255.0'
        option ipaddr '192.168.1.100'
        option gateway '192.168.1.1'

config zone
        option name 'wan'
        option network 'wan gm'
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'

# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0.2
......
......

ifconfig eth0.2:0 192.168.1.100 netmask 255.255.255.0
iptables -t nat -I POSTROUTING -o eth0.2 -d 192.168.1.0/24 -j MASQUERADE

ifconfig eth0.2:0 down

/etc/init.d/network reload

reboot

chmod [选项] 权限模式 文件名/目录名

chmod 755 file 
chmod rwxr-xr-x file

chmod u+x file.sh

chmod g-w dir 

chmod o+r file

chmod a+r file.txt

top - 14:28:52 up 39 days, 20:56,  1 user,  load average: 0.20, 0.42, 0.52

Tasks: 236 total,   2 running, 234 sleeping,   0 stopped,   0 zombie

%Cpu(s):  2.9 us,  1.4 sy,  0.0 ni, 95.1 id,  0.5 wa,  0.0 hi,  0.1 si,  0.0 st

GiB Mem :   62.645 total,    4.274 free,   22.042 used,   36.329 buff/cache

GiB Swap:   64.000 total,   63.203 free,    0.797 used.   39.949 avail Mem

 PID USER       PR   NI   VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
23090 root      20   0  9.793g 818716   7460 S  14.6  1.2   1971:30 java
 3617 root      20   0 20.274g 220676   7468 S  12.6  0.3  10874:44 java
23496 root      20   0  9.780g 444548   7524 S   8.3  0.7   1228:19 java
 2648 elastic+  20   0 50.123g 1.527g   7612 S   7.3  2.4 662:56.49 java

(参数) -> {函数体}

Consumer<String> c = new Consumer<String>() {
    @Override
    public void accept(String str) {
        System.out.println("msg=" + str);
    }
};

Consumer<String> c1 = (String str) -> {
    System.out.println("msg=" + str);
};

Thread t = new Thread(() -> {
    System.out.print("Lambda!");
    System.out.print("Do Something...");
});
t.run();

Consumer<String> c1 = (str) -> {
    System.out.println("msg=" + str);
};

Consumer<String> c2 = str -> {
    System.out.println("msg=" + str);
};

Consumer<String> c3 = str -> System.out.println(str);

Supplier<String> s1 = () -> {
    return "Lambad!";
};

Supplier<String> s2 = () -> "Lambad!";

Supplier<User> s3 = () -> new User("张三", 20);

Consumer<String> c4 = System.out::println;

Supplier<User> s4 = User::new;

Supplier<User> s5 = User::getInstance;

BiFunction<Integer, Integer, Integer> bf = (x, y) -> x > y ? x : y;
# 可以写成
BiFunction<Integer, Integer, Integer> bf1 = Math::max;

interface A {
     // 默认方法
    default void say() {
        System.out.println("hello");
    }
}

class C1 implements A {

}

public static void main(String[] args) {
    C1 c1 = new C1();
    // 自动继承
    c1.say();
}

hello

class C1 implements A {
    @Override
    public void say() {
        System.out.println("C1 hello");
    }
}

C1 hello

class C2 extends C1{
    
}

public static void main(String[] args) {
   C2 c2 = new C2();
   c2.say();
}

C1 hello

interface A {
    default void say() {
        System.out.println("[interface A] say hello");
    }
}

interface B {
    default void say() {
        System.out.println("[interface B] say hello");
    }
}

class C1 implements A, B {
    @Override
    public void say() {
        System.out.println("需要重写say方法，否则编译器不知道是调用 A.say 还是 B.say");
    }
}

class C1 implements A, B {
    @Override
    public void say() {
        A.super.say();
    }
}

[interface A] say hello

interface A {
    static String STR = "静态字段可以被继承";
    static void sayA() {
        System.out.println("static sayA");
    }
}

class C1 implements A {
}

//main
public static void main(String[] args) {
    // 通过接口名称调用接口的静态方法
    A.sayA();

    // 不能通过子类实例调用 new C1().sayA()
    // 也不能通过子类调用 C1.sayA()
    
    //可以通过子类实例获取静态字段值
    System.out.println(new C1().STR);
}

@FunctionalInterface
public interface FunctionalInterfaceT1<T> {

    // 抽象方法
    void doSomething(T t);

    // Object类中的方法
    boolean equals(Object obj);

    // 默认方法
    default void printT(T t) {
        System.out.println(t);
    }

    // 默认方法2
    default void printT2(T t) {
        System.out.println(t);
    }

    // 静态方法
    public static void print() {
        System.out.println("FunctionalInterfaceT1.print");
    }
}

BiFunction<Integer, Integer, Integer> bf = Math::max;
System.out.println(bf.apply(1, 3));

Consumer<String> c = System.out::println;
c.accept("hello");

String[] stringArray = { "Barbara", "James", "Mary", "John", "Patricia", "Robert", "Michael", "Linda" };
Arrays.sort(stringArray, String::compareToIgnoreCase);
Arrays.stream(stringArray).forEach(System.out::println);

Supplier<User> s = User::new;

# change this to reflect your shard path, the format is
# {path.data}/{cluster_name}/nodes/{node_id}/indices/{index_name}/{shard_id}/index/

$ export SHARD_PATH=data/elasticsearch/nodes/0/indices/foo/0/index/
$ java -cp lib/elasticsearch-*.jar:lib/*:lib/sigar/* -ea:org.apache.lucene... org.apache.lucene.index.CheckIndex $SHARD_PATH

 java -cp lib/elasticsearch-*.jar:lib/*:lib/sigar/* -ea:org.apache.lucene... org.apache.lucene.index.CheckIndex

ERROR: index path not specified
Usage: java org.apache.lucene.index.CheckIndex pathToIndex [-exorcise] [-crossCheckTermVectors] [-segment X] [-segment Y] [-dir-impl X]

  -exorcise: actually write a new segments_N file, removing any problematic segments
  -fast: just verify file checksums, omitting logical integrity checks
  -crossCheckTermVectors: verifies that term vectors match postings; THIS IS VERY SLOW!
  -codec X: when exorcising, codec to write the new segments_N file with
  -verbose: print additional details
  -segment X: only check the specified segments.  This can be specified multiple
              times, to check more than one segment, eg '-segment _2 -segment _a'.
              You can't use this with the -exorcise option
  -dir-impl X: use a specific FSDirectory implementation. If no package is specified the org.apache.lucene.store package will be used.

**WARNING**: -exorcise *LOSES DATA*. This should only be used on an emergency basis as it will cause
documents (perhaps many) to be permanently removed from the index.  Always make
a backup copy of your index before running this!  Do not run this tool on an index
that is actively being written to.  You have been warned!

Run without -exorcise, this tool will open the index, report version information
and report any exceptions it hits and what action it would take if -exorcise were
specified.  With -exorcise, this tool will remove any segments that have issues and
write a new segments_N file.  This means all documents contained in the affected
segments will be removed.

This tool exits with exit code 1 if the index cannot be opened or has any
corruption, else 0.

$ java -cp lib/elasticsearch-*.jar:lib/*:lib/sigar/* -ea:org.apache.lucene... org.apache.lucene.index.CheckIndex $SHARD_PATH -exorcise

git rebase master

git rebase -i B 

git init

vi aaa.txt

git checkout -b dev

vi bbb.txt

git add .

git commit

git checkout master

vi aaa.txt

git add .

git commit

git checkout dev

git merge master

$ git log --graph --pretty=oneline
*   baba7341616a7fd6e6932bf76a90fca9782a8e54 (HEAD -> dev) Merge branch 'master' into dev
|\
| * 3c408871ffcc5cfc37a295ecf936a23aff808c68 (master) master modified aaa.txt
* | a9dc6221ce4b152b292cbcd4e242026edbb7d379 dev branch add bbb.txt file
|/
* 171e52a8cd9c96706cb0112013d556b62932ee39 first commit

$ git rebase master

$ git log --oneline --graph
* 6879874 (HEAD -> dev) dev branch add bbb.txt file
* 3c40887 (master) master modified aaa.txt
* 171e52a first commit

git rebase --continue

git rebase —abort

$ git checkout master

$ git merge dev

$ git log --oneline --graph

git add/rm <conflicted_files>

git rebase --continue

git rebase --skip

git rebase --abort

git init

vim aaa.txt

git add .

git commit -m "add a file"

git clone file file:///d/test/repository/git1/.git/

git pull

git checkout -b dev

vim bbb.txt

git add .

git commit

git push

# 需要指定远程的分支
git push --set-upstream origin dev

$ git push
Enumerating objects: 4, done.
Counting objects: 100% (4/4), done.
Delta compression using up to 12 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 297 bytes | 297.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
remote: error: refusing to update checked out branch: refs/heads/dev
remote: error: By default, updating the current branch in a non-bare repository
remote: is denied, because it will make the index and work tree inconsistent
remote: with what you pushed, and will require 'git reset --hard' to match
remote: the work tree to HEAD.
remote:
remote: You can set the 'receive.denyCurrentBranch' configuration variable
remote: to 'ignore' or 'warn' in the remote repository to allow pushing into
remote: its current branch; however, this is not recommended unless you
remote: arranged to update its work tree to match what you pushed in some
remote: other way.
remote:
remote: To squelch this message and still keep the default behaviour, set
remote: 'receive.denyCurrentBranch' configuration variable to 'refuse'.
To file:///d/test/repository/git1/.git/
 ! [remote rejected] dev -> dev (branch is currently checked out)
error: failed to push some refs to 'file:///d/test/repository/git1/.git/'

$ git config receive.denyCurrentBranch ignore

mysql> SELECT VERSION();
+------------+
| VERSION()  |
+------------+
| 5.6.41-log |
+------------+
1 row in set (0.09 sec)

mysql> SHOW VARIABLES LIKE 'version';
+---------------+------------+
| Variable_name | Value      |
+---------------+------------+
| version       | 5.6.41-log |
+---------------+------------+
1 row in set (0.14 sec)

mysql> SELECT @@SESSION.tx_isolation;
+------------------------+
| @@SESSION.tx_isolation |
+------------------------+
| READ-COMMITTED         |
+------------------------+
1 row in set (0.07 sec)

mysql> SELECT @@GLOBAL.tx_isolation;
+-----------------------+
| @@GLOBAL.tx_isolation |
+-----------------------+
| READ-COMMITTED        |
+-----------------------+
1 row in set (0.06 sec)

mysql> SHOW VARIABLES LIKE 'tx_isolation';
+---------------+----------------+
| Variable_name | Value          |
+---------------+----------------+
| tx_isolation  | READ-COMMITTED |
+---------------+----------------+
1 row in set (0.08 sec)

# 开启事务
START TRANSACTION;

# 执行操作A...
# 执行操作B...

# 提交或回滚事务
COMMIT;
ROLLBACK;

SELECT * FROM INFORMATION_SCHEMA.INNODB_TRX;

SELECT TIMESTAMPDIFF(SECOND, t.trx_started, NOW()) AS trx_runtime_seconds,t.* FROM information_schema.INNODB_TRX t;

SELECT 
    trx_id, 
    trx_state, 
    trx_started, 
    trx_wait_started, 
    TIMESTAMPDIFF(SECOND, trx_wait_started, NOW()) AS wait_time_seconds,
    trx_requested_lock_id
FROM 
    INFORMATION_SCHEMA.INNODB_TRX
WHERE 
    trx_state = 'LOCK WAIT';

1213 - Deadlock found when trying to get lock; try restarting transaction

SHOW PROCESSLIST;
SHOW FULL PROCESSLIST;

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE DB = 'test';

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE TIME > 60;

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE LIKE '%lock%';

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'your_user';

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep';

KILL [CONNECTION | QUERY] thread_id;

KILL 1234;

KILL QUERY 1234;

-- 查看当前会话超时设置
SHOW VARIABLES LIKE 'wait_timeout';

-- 查看全局超时设置
SHOW VARIABLES LIKE 'interactive_timeout';

-- 修改会话超时（单位：秒）
SET @@SESSION.wait_timeout = 28800;  -- 8小时

-- 修改全局超时（单位：秒）
SET @@GLOBAL.wait_timeout = 28800;   -- 8小时

# 查看，默认是50秒
show variables like 'innodb_lock_wait_timeout';

# 设置锁等待超时时间为 360 秒
set @@SESSION.innodb_lock_wait_timeout=360;

# 设置全局锁等待超时时间
SET GLOBAL innodb_lock_wait_timeout = 120;