The difference between caching and buffering
The cache is used to load data "read" from the disk,
Buffer (buffer) is used to load data "written" to the hard disk.
vmstat: The vmstat command is the most common Linux / Unix monitoring tool. It can display the status of the server at a given time interval, including the server's CPU usage, memory usage, virtual memory exchange, IO read and write.
free: Used to display the memory status. Display memory usage, including physical memory, virtual swap file memory, shared memory segments, and buffers used by the system core.
cat / proc / cpuinfo: view cpu memory
uptime: equivalent to the first line of the top command
uname [options]: view the system kernel (-a: view all relevant information of the system; -r: view the kernel version; -s: view the kernel name)
file / bin / ls: can view the number of operating bits of the system (64/32)
lsof | more: View files called by all processes in the system
lsof / sbin / init: Query a file to be called by that process (the file can only be created by the system, such as init)
lsof -c httpd: check which files are called by httpd process
lsof -u root: According to the user name, query a user's process call file name