free && sync && echo 3 > /proc/sys/vm/drop_caches && free

Release memory used by the Linux kernel on caches

The Linux kernel uses unused memory in caches. When you execute "free" you never get the "real" available memory.
Sample Output
             total       used       free     shared    buffers     cached
Mem:       1018916     980832      38084          0      46924     355764
-/+ buffers/cache:     578144     440772
Swap:      2064376        128    2064248
             total       used       free     shared    buffers     cached
Mem:       1018916     685008     333908          0        224     108252
-/+ buffers/cache:     576532     442384
Swap:      2064376        128    2064248

38
2009-08-05 23:44:34

6 Alternatives + Submit Alt

What Others Think

Another way: add up the "MemFree", "Buffers", and "Cached" amounts in /proc/meminfo.
bwoodacre · 459 weeks and 1 day ago
really saved my bacon today!
linuxrawkstar · 394 weeks and 6 days ago
DON'T DO THIS! This command shows a serious lack of understanding by the author and those who voted it up. You don't want to clear your disk cache because its a helpful thing. If you want to know how much memory you have available for applications, look at the number in the free column on the -/+ buffers/cache line. For more information, see http://www.linuxatemyram.com/
deltaray · 296 weeks and 1 day ago
DON'T DO THIS! This command shows a serious lack of understanding by the author and those who voted it up. You don't want to clear your disk cache because its a helpful thing. If you want to know how much memory you have available for applications, look at the number in the free column on the -/+ buffers/cache line. For more information, see http://www.linuxatemyram.com/
deltaray · 296 weeks and 1 day ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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