Memory Usage

The free command displays the total amount of physical memory and swap space for the system as well as the amount of memory that is in use, free, shared, in kernel buffers, and cached. Output from the free command might look like this:

            total   used     free     shared      buffers       cached Mem:       256812  240668   16144     105176       50520        81848 -/+ buffers/cache: 108300  148512 Swap:      265032     780  264252

The command free -m shows the same information in megabytes, which are easier to read.

            total   used      free      shared       buffers   cached Mem:         250     235       15         102          49        79 -/+ buffers/cache:   105      145 Swap:     258      0        258

If you prefer a graphical interface for free, use the GNOME System Monitor. To start it from the desktop, go to the Main Menu Button (on the Panel) > System Tools > System Monitor or type gnome-system-monitor at a shell prompt from within the X Window System. Then choose the System Monitor tab.