See the use of hard disk

1)displayed in KB
df -k

2)displayed in MB,only show size
du -s www

3)displayed in MB,show sub-directory size
du -h www

View the resource used by java

1)see the process contains java
ps -ef | grep JAVA
refrence :linux ps command

2)view the process
top -H

Find the possibility of high load

1)see high CPU usage by processes
ps ux

2)see usage of threads which belong to java process

ps -Lp
jstack 15047


repalce from line 1 to the end

file system

├── / root directory
├── bin store the user binary files
├── boot store the kernel boot configuration file
├── dev store the device file:devtmpfs
├── etc store the system configuration file
├── home user home directory
├── lib Dynamic shared library
├── lost+found recovery file
├── media Removable storage medium mountpoints
├── mnt the temporary file system mount point
├── opt Additional application package
├── proc System memory mapping directory to provide the kernel and process information
├── root root User home directory:ext4
├── sbin store binary files
├── srv Storage service related data
├── sys sys The virtual file system mount point
├── tmp store temporary file
├── usr store user application program
└── var store file :Mail, system log, etc

Free port

1)Check the port
netstat -apn | grep port

2)query process
ps -ef | grep PID

3)kill process
kill -9 PID