Red Hat

Code:

             total       used       free     shared    buffers     cached
Mem:          3816       3569        247          0        118       2397
-/+ buffers/cache:       1053       2763
Swap:         3823         13       3810

ok, this is the output for my laptop.

The free command is used to display the amount of free and used memory on a system. The -m option tells free to print the output in MB.

My laptop has 4Gb currently.

Linux attempts to utilize all of the memory on the system and not leave any sitting idle, like some other operating systems have done over time. Memory will be used for the OS and applications, but the remainder will be used as "buffers and cache". The kernel will keep items in memory that are needed often or are predicted to be needed for faster access. The memory used for "buffers and cache" is available for applications or the OS to use. If required, it is quickly flushed and used.

To find the actual available memory on my system, take the last number on the Mem line (247) and add it to the last number on the Mem line (2397). So currently, I have about 3G of memory available.

Most of this information is available via the manpage and simple google searches. Take a look and you should have all of your questions answered.

Thanks for your answer. I wanted to add something, if we add 118 to the total of 2397 & 247, it would be 2762 which is very near the free memory on line 2, 2763. Please confirm on this.

Also, as per your answer, the architecture of Linux is to utilize all the memory on the system.