Free (command)
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free is a UNIX command which displays the total amount of free and used physical and swap memory in the system, as well as the shared memory and buffers used by the kernel.
Syntax
free [-b|-k|-m] [-o] [-s delay] [-t] [-V]
Options
- [-b|-k|-m|-g]
- The -b switch displays the amount of memory in bytes; the -k switch (set by default) displays it in kilobytes; the -m switch in megabytes and the -g switch in gigabytes.
- [-t]
- Displays a line containing the totals.
- [-o]
- Disables the display of a "buffer adjusted" line. Unless specified free subtracts/adds buffer memory from/to the used/free memory reports (respectively!).
- [-s]
- Activates continuous polling delay seconds apart. You may actually specify any floating point number for delay, usleep(3) is used for microsecond resolution delay times.
- [-v]
- Displays version information.
Examples
Invoked on a machine with 512 MB of RAM, with the "-m" switch (to give counts in megabytes):
$ free -m
total used free shared buffers cached
Mem: 499 490 9 0 91 117
-/+ buffers/cache: 281 218
Swap: 964 6 958
$