MySQL Show stauts state variable description

Aborted_clients	Indicates the number of failed connections due to some reason that the client did not close the connection properly. This can happen if the customer does not adjust the mysql_close () function before exiting, or if the wait_timeout or interactive_timeout limit has been exceeded, or if the client program was shut down during transmission.
Aborted_connects	Indicates the number of failed attempts to connect to MySQL. This situation occurs when a client attempts to connect with the wrong password, and when there is no permission to connect, it takes more time to get the connected packet than the connect_timeout limit of seconds, or if the packet does not contain the correct information.
Bytes_received	The number of bytes that have been received from the customer.
Bytes_sent	The number of bytes that have been sent to all customers.
Com_[statement]	One of these variables for each statement. The value of the variable indicates how many times the statement was executed, such as Com_select, which indicates how many times the query statement was executed.
Connections	Number of attempts to connect to the MySQL server.
Created_tmp_disk_tables	The number of hidden temporary tables generated on the disk when the statement is executed
Created_tmp_tables	The number of hidden temporary tables generated in memory when the statement is executed
Created_tmp_files	Number of temporary files generated by mysqld
Delayed_insert_threads	Number of threads currently in use for deferred insert handles
Delayed_writes	Number of records written by the insert delayed statement
Delayed_errors	The record that is written by the insert delayed statement when an error occurs. The most common mistake is to copy the key
Flush_commands	Number of flush statements executed
Handler_commit	Number of internal commit commands
Handler_delete	Number of rows deleted from a table
Handler_read_first	The number of times the first entry in an index is read, usually a full index scan (for example, assuming Indexed_col is indexed, and the statement select Indexed_col from tablename causes a full index scan)
Handler_read_key	The number of requests that use the index when reading a row of data. If you use an index on a query, you want this value to increase quickly
Handler_read_next	The number of requests to read the next row of data in an indexed order. This value increases if a full index is used to scan, or if an index is queried in a constant range
Handler_read_prev	The number of requests to read the previous row of data in the order of the index. This variable value is used by the statement of the Select FieldList Order by fields desc type
Handler_read_rnd	The number of requests to read a row of data at a fixed location. Query operations that require results to be saved increase the value of this counter
Handler_read_rnd_next	The number of requests to read the next row of data in the data file. Generally, this value cannot be too high, because this means that the query operation will not use the index and must read from the data file
Handler_rollback	Number of internal rollback commands
Handler_update	Number of requests to update a record in a table
Handler_write	Number of requests to insert a record in a table
Key_blocks_used	Number of blocks of data used in the key's cache
Key_read_requests	The number of requests that caused the data block to read the key from the key's cache. The ratio of key_reads to key_read_requests should not be higher than 1:100 (that is, 1:10 is bad)
Key_reads	The number of physical read operations that caused the data block to read the key from the disk.
Key_write_requests	The number of requests that caused the key's data block to be written to the cache
Key_writes	The number of physical writes to the data block where the key was written to the disk
Max_used_connections	The maximum number of connections that are being used at any time
Not_flushed_key_blocks	The number of data blocks in the key cache that have changed but have not yet been flushed to the keys on the disk
Not_flushed_delayed_rows	The number of records currently waiting to be written in the Insert delay queue
Open_tables	The number of tables currently open
Open_files	The number of files currently open
Open_streams	The number of stream data that is currently open. These stream data are used primarily for logging
Opened_tables	The number of tables that have been opened
Questions	Total number of initial query operations
Qcache_queries_in_cache	Number of queries in the cache
Qcache_inserts	The number of hits in the query added to the cache divided by the number of inserts is not in the ratio; 1 minus this value is the hit rate.
Qcache_hits	Number of query cache accesses
Qcache_lowmem_prunes	The number of times the cache appears to be out of memory and must be cleaned up to provide space for more queries. This number is best for long periods of time; If the number is growing, it means that it may be very fragmented or that there is little memory. (The above free_blocks and free_memory can tell you what kind of situation).
Qcache_not_cached	Number of queries that are not cached (due to too large, or because of Query_cache_type)
Qcache_free_memory	The number of memory that can still be used for query caching
Qcache_free_blocks	The number of free memory blocks in the query cache, indicating that there may be fragments
Qcache_total_blocks	The total number of data blocks in the query cache
Rpl_status	Status of full replication (this variable is only used in the version after MySQL 4)
Select_full_join	The number of joins that have been executed that do not use the index. The value of this variable cannot be set too high

Real-world development, do not need to understand all of these variable information situation, in fact, you can try Mysqlreport command, Mysqlreport is standing on the shoulders of giants, it does is to show status and Sho InnoDB Status results in a series of post-processing, the more we care about the content in a more readable way to present

For some of the comments above:

If the opened_tables is too large, your table_cache variable may be too small.
If the key_reads is too big, then your key_cache may be too small. Cache hit rates can be computed using key_reads/key_read_requests.
If the handler_read_rnd is too large, then you are likely to have a large number of queries that require MySQL to scan the entire table or you have a join that does not use the key values correctly.
Show variables shows the values of some MySQL system variables, and you can also use the mysqladmin variables command to get this information. If the defaults are not appropriate, you can use command-line options to set the majority of these variables at mysqld startup.

Show Processlist shows which thread is running and you can also use the Mysqladmin processlist command to get this information. If you have process permissions, you can see all the threads, otherwise you can only see your own threads. See 7.20 kill syntax. If you do not use the full option, only the first 100 characters of each query are displayed.

Show grants for user lists authorization commands that must be issued with a duplicate authorization for a user