free Display amount of free and used memory in the system
free [-b | -k | -m] [-o] [-s delay ] [-t] [-l] [-V]
TAG | DESCRIPTION |
---|---|
-b | The -b switch displays the amount of memory in bytes; the -k switch (set by default) displays it in kilobytes; the -m switch displays it in megabytes. |
-t | The -t switch displays a line containing the totals. |
-o | The -o switch disables the display of a "buffer adjusted" line. If the -o option is not specified, free subtracts buffer memory from the used memory and adds it to the free memory reported |
-s | The -s switch 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. |
-l | The -l switch shows detailed low and high memory statistics |
-V | The -V switch displays version information. |
x | Extract members (named member) from the freechive. You can use the v modifier with this operation, to request that free list each name as it extracts it.
If you do not specify a member, all files in the freechive freee extracted. Files cannot be extracted from a thin freechive. |
EXAMPLE-1:
Free command used to check the used and available space of physical memory and swap memory in KB.
# free
output:
# free
total used free shared buffers cached
Mem: 1000192 465672 534520 176 55088 175212
-/+ buffers/cache: 235372 764820
Swap: 1044476 12372 1032104
EXAMPLE-2:
Free command with option -b, display the size of memory in Bytes.
# free -b
output:
# free -b
total used free shared buffers cached
Mem: 1024196608 476831744 547364864 180224 56418304 179400704
-/+ buffers/cache: 241012736 783183872
Swap: 1069543424 12668928 1056874496
EXAMPLE-3:
Free command with option -k, display the size of memory in (KB) Kilobytes.
# free -k
output:
# free -k
total used free shared buffers cached
Mem: 1000192 465640 534552 176 55096 175196
-/+ buffers/cache: 235348 764844
Swap: 1044476 12372 1032104
EXAMPLE-4:
To see the size of the memory in (MB) Megabytes use option as -m.
# free -m
output:
# free -m
total used free shared buffers cached
Mem: 976 454 522 0 53 171
-/+ buffers/cache: 229 746
Swap: 1019 12 1007
EXAMPLE-5:
Using -g option with free command, would display the size of the memory in GB(Gigabytes)
# free -g
output:
# free -g
total used free shared buffers cached
Mem: 0 0 0 0 0 0
-/+ buffers/cache: 0 0
Swap: 0 0 0
EXAMPLE-6:
Free command with -t option, will list the total line at the end.
# free -t
output:
# free -t
total used free shared buffers cached
Mem: 1000192 465640 534552 176 55096 175196
-/+ buffers/cache: 235348 764844
Swap: 1044476 12372 1032104
Total: 2044668 478012 1566656
EXAMPLE-7:
By default the free command display “buffer adjusted” line, to disable this line use option as -o
# free -o
output:
# free -o
total used free shared buffers cached
Mem: 1000192 465640 534552 176 55096 175196
Swap: 1044476 12372 1032104
EXAMPLE-8:
The -s option with number, used to update free command at regular intervals.
# free -s 5
This command displays output every 5 seconds.
output:
# free -s 5
total used free shared buffers cached
Mem: 1000192 465640 534552 176 55096 175196
-/+ buffers/cache: 235348 764844
Swap: 1044476 12372 1032104
total used free shared buffers cached
Mem: 1000192 465656 534536 176 55096 175196
-/+ buffers/cache: 235364 764828
Swap: 1044476 12372 1032104
total used free shared buffers cached
Mem: 1000192 465656 534536 176 55096 175196
-/+ buffers/cache: 235364 764828
Swap: 1044476 12372 1032104
EXAMPLE-9:
* The -l switch displays detailed high and low memory size statistics.
# free -lPrint
output:
# free -l
total used free shared buffers cached
Mem: 1000192 465640 534552 176 55096 175196
Low: 1000192 465640 534552
High: 0 0 0
-/+ buffers/cache: 235348 764844
Swap: 1044476 12372 1032104