Running php on Hortonworks sandbox

I am trying to design my front end for my back end services which involves hadoop and hive. I was successfully able to open up XAMPP server on port 8085 of Hortonworks 2.4. For that I had to stop httpd services already running. I was also successfull in writing php codes which talked with mySQL services. However some thing astonishing which I have noticed right away is that on firing hadoop or hive or ambari commands, this is what I am getting –
-bash: hadoop: command not found
-bash: hive: command not found
-bash: ambari: command not found
I think there is some problem with PATH Variables. Can u help me identify root cause and is it possible to run XAMPP services from inside of HDP 2.4 (which uses CentOS 6.9) ?

Source: stackoverflow-php

Xampp mysql Error: MySQL shutdown unexpectedly

when I starting mysql, giving the following error:

17:43:13  [mysql]   Error: MySQL shutdown unexpectedly.
17:43:13  [mysql]   This may be due to a blocked port, missing dependencies, 
17:43:13  [mysql]   improper privileges, a crash, or a shutdown by another method.
17:43:13  [mysql]   Press the Logs button to view error logs and check
17:43:13  [mysql]   the Windows Event Viewer for more clues
17:43:13  [mysql]   If you need more help, copy and post this
17:43:13  [mysql]   entire log window on the forums

then, I check the mysql_error.log:

    2017-05-03 17:39:39 202c InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in        future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
    170503 17:39:39 [Note] InnoDB: Using mutexes to ref count buffer pool pages
    170503 17:39:39 [Note] InnoDB: The InnoDB memory heap is disabled
    170503 17:39:39 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions
    170503 17:39:39 [Note] InnoDB: Memory barrier is not used
    170503 17:39:39 [Note] InnoDB: Compressed tables use zlib 1.2.3
    170503 17:39:39 [Note] InnoDB: Not using CPU crc32 instructions
    170503 17:39:39 [Note] InnoDB: Initializing buffer pool, size = 16.0M
    170503 17:39:39 [Note] InnoDB: Completed initialization of buffer pool
    170503 17:39:39 [Note] InnoDB: Highest supported file format is Barracuda.
    170503 17:39:39 [Note] InnoDB: The log sequence numbers 0 and 0 in ibdata files do not match the log sequence number 1600674 in         the ib_logfiles!
    170503 17:39:39 [Note] InnoDB: Database was not shutdown normally!
    170503 17:39:39 [Note] InnoDB: Starting crash recovery.
    170503 17:39:39 [Note] InnoDB: Reading tablespace information from the .ibd files...
    170503 17:39:39 [Note] InnoDB: Restoring possible half-written data pages 
    170503 17:39:39 [Note] InnoDB: from the doublewrite buffer...
    170503 17:39:39 [Note] InnoDB: 128 rollback segment(s) are active.
    170503 17:39:39 [Note] InnoDB: Waiting for purge to start
    170503 17:39:40 [Note] InnoDB:  Percona XtraDB ( 5.6.22-72.0 started; log sequence number 1600674
    170503 17:39:40 [Note] Plugin 'FEEDBACK' is disabled.
    170503 17:39:40 [Note] Server socket created on IP: '::'.   

finally, I moved xampp/mysql/backup files into xampp/mysql/data and run mysql again.Then, it worked!But I don’t know why.What led to this problem.

Hope someone doubts for me!

Source: stackoverflow-php