free command

LINUX-Frequently used commands

free command Checking the memory status of Linux
free   [Option]
The free command is a command to check the memory status of Linux.
The items displayed include total memory, used space, free space, buffers, and cache. These memory status is displayed in real time.
The free command displays the data based on the “/proc/meminfo” file, so you can run “cat /proc/meminfo will give you the same result.
Frequently used options
-b   Display memory capacity in bytes
-k   Display memory capacity in kilobytes
-m  Display memory capacity in megabytes
-g   Display memory capacity in gigabytes
-t    Show total memory and swap space
Example: Checking the memory status of Linux.
$ free

                       total         used         free     shared     buffers     cached
Mem:      8061116    7944800    116316         220      7172     105892
/+ buffers/cache:     7831736    229380
Swap:      2097148    2097148             0
MemMain memory size(※1)
/+buffers/cacheMemory size including page cache and buffer cache
SwapMemory size of the swap area
totalTotal capacity(※2)
usedCapacity for use
freefree space
sharedShared memory (memory in an area that can be shared between processes)
buffersbuffer cache
cachedpage cache
※1:The size of the main memory does not include the buffer cache and page cache.
※2:Memory used by the OS for disk cache (page cache, buffer cache, etc.) is also included.
Example: Display the total physical memory and swap space
$ free mt  

                      total      used       free    shared     buffers    cached
Mem:             7872      7750        121           0             3           89
/+ buffers/cache:         7657        214 
Swap:           2047      2047           0
Total:               9920       9798         121