Name

free [options] — procps

Synopsis

/usr/bin stdin stdout - file -- opt --help --version

The free command displays memory usage in kilobytes:

$ free
             total       used       free     shared
buffers     cached
Mem:        523812     491944      31868          0
      67856     199276
-/+ buffers/cache:     224812     299000
Swap:       530104          0     530104

The Linux kernel reserves as much memory as possible for caching purposes, so your best estimate of free RAM in the preceding output is 299000.

Useful options

-s N

Run continuously and update the display every N seconds.

-b

-m

Display amounts in bytes or megabytes, respectively.

-t

Add a totals line at the bottom.

-o

Don’t display the “buffers/cache” line.

Get Linux Pocket Guide now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial