Free unused memory currently unavailable

dd if=/dev/zero of=junk bs=1M count=1K
This is an useful command for when your OS is reporting less free RAM than it actually has. In case terminated processes did not free their variables correctly, the previously allocated RAM might make a bit sluggis over time. This command then creates a huge file made out of zeroes and then removes it, thus freeing the amount of memory occupied by the file in the RAM. In this example, the sequence will free up to 1GB(1M * 1K) of unused RAM. This will not free memory which is genuinely being used by active processes.

By: guedesav
2009-11-01 23:45:51

What Others Think

To free cached memory, you can also do: sudo echo 3 > /proc/sys/vm/drop_caches Then in order allow caching again sudo echo 0 > /proc/sys/vm/drop_caches
alperyilmaz · 624 weeks and 2 days ago
I am lost. Where in the command does it remove it??
DaveQB · 624 weeks and 2 days ago
When it removes the file.
guedesav · 623 weeks and 6 days 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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