ubuntu16.04 viewing system available memory

Free-m View memory status (in megabytes)

The MEM line shows how memory is used from a system point of view, and total is the amount of memory available to the system, equal to the system physical memory minus the kernel's reserved memory . Buffers and cached are memory used by the system as buffers. The buffers is associated with a block device, contains the file system metadata, and tracks changes in the block. The cache contains only the file itself.

-/+ buffers/cache rows Display memory information from the user's perspective, and the available memory is equal to the number of mem rows used column values minus the size of buffers and cached memory. Because buffers and cached are set up by the operating system to speed up system operation, they can be used directly for users when they need it.

The free command is detailed:
Function Description: Displays the memory status.
Syntax: free [-bkmotv][-s]
Note: The free instruction shows memory usage, including physical memory, virtual exchange of document memory, shared memory segments, and buffers used by the system core.
Parameters
-B Displays memory usage in bytes.
-K displays memory usage in kilobytes.
-m displays memory usage in megabytes.
-O does not display buffer throttling columns.
-S continuously observes memory usage.
-T displays the memory sum column.
-V Displays version information.

The MEM line shows how memory is used from a system point of view, and total is the amount of memory available to the system, equal to the system physical memory minus the kernel's reserved memory. Buffers and cached are memory used by the system as buffers. The buffers is associated with a block device, contains the file system metadata, and tracks changes in the block. The cache contains only the file itself.

-/+ buffers/cache rows Display memory information from the user's perspective, and the available memory is equal to the number of mem rows used column values minus the size of buffers and cached memory. Because buffers and cached are set up by the operating system to speed up system operation, they can only be used by users when they need it.

Top and the Vmstat The system memory information is also displayed, similar to the display results for free.

The free command is detailed:
Function Description: Displays the memory status.
Syntax: free [-bkmotv][-s]
Note: The free instruction shows memory usage, including physical memory, virtual exchange of document memory, shared memory segments, and buffers used by the system core.
Parameters
-B Displays memory usage in bytes.
-K displays memory usage in kilobytes.
-m displays memory usage in megabytes.
-O does not display buffer throttling columns.
-S continuously observes memory usage.
-T displays the memory sum column.
-V Displays version information.

ubuntu16.04 viewing system available memory