Free command

From NetworkCommands

A command line program available on most Linux platforms; used to display physical memory usage statistics.

Usage Syntax

free [options]

Common options include;

-b - display information in bytes
-k - display information in kilobytes
-m - display information in megabytes
-g - display information in gigabytes
-l - display information about low and high memory usage
-c number - display information the specified number of times and then exit, must be used with the -s option
-s number - repeat, pausing the specified number of seconds, continues indefinately unless the -c option has been used

Usage Examples

free - display summary physical memory usage information

free -mc 2 -s 2 - display summary physical memory usage information, in megabytes, three times with a two second interval

Usage Notes

The information displayed is actually stored in file: /proc/meminfo

Linux Usage Notes

With most Linux or Unix commands;

Brief help can be displayed using the option/keyword: -h or --help, for example: chmod --help
A full command manual can be displayed using the man command followed by the command name, for example: man chmod
Sometimes 'info' pages are used instead of or to provide more information than man pages; for example: info chmod
Version information can be display using the option/keyword: -v or --version, for example: chmod --version

Typical Output

             total       used       free     shared    buffers     cached
Mem:           371        361         10          0        103         82
-/+ buffers/cache:        175        196
Swap:         3014         78       2935