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 used, free, shared, in kernel buffers, and cached. Following is a sample output of the free command:

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

Using the free -m command 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, you can use the GNOME System Monitor. To start the System Monitor from the desktop, click the Main Menu button and choose System Tools > System Monitor (or type gnome-system-monitor at a shell prompt from within X Window System). Then choose the System Monitor tab.

25-2. : GNOME System Monitor — System Monitor Tab