用途
查看系统内存(物理/虚拟/缓存/共享)使用情况
用法
free [-b | -k | -m | -g | -h] [-o] [-s delay ] [-c count ] [-a] [-t] [-l] [-V]
常用选项
| 选项 | 含义 | 说明 |
|---|---|---|
| -b | 单位byte | switch displays the amount of memory in bytes; |
| -k | 单位k | switch (set by default) displays it in kilobytes; |
| -m | 单位m | switch displays it in megabytes; |
| -g | 单位g | switch displays it in gigabytes; |
| -h | 人类可读方式 | switch displays all output fields automatically scaled to the shortest (three digit) representation including the unit. That makes the values human readable. |
| -t | 显示汇总行 | switch displays a line containing the totals. |
| -o | disables the display of a "buffer adjusted" line | 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 间隔秒数 | 间隔几秒重复刷新显示 | 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. |
| -c 次数 | 重复刷新显示总次数 | switch used together with the -s switch interrupts the polling after count repetitions. |
| -l | 显示low行 | switch shows detailed low and high memory statistics. |
| -a | 显示可用内存 | switch shows the available memory (if supported by the running kernel and enabled with sysctl -w vm.mem-info_legacy_layout=0 ; shows zero when unsupported or disabled). The produced output is wider than 80 characters. |
| -V | 显示程序版本信息 | switch displays version information. |
实践
1 显示内存使用情况
[root@vm ~]# free -h
total used free shared buffers cached
Mem: 2.9G 2.7G 209M 37M 11M 185M
-/+ buffers/cache: 2.5G 405M
Swap: 1.6G 1.2G 415M
参考资料
【1】man free
【2】每天一个linux命令（45）：free 命令
http://www.cnblogs.com/peida/archive/2012/12/25/2831814.html
【3】Linux上的free命令详解
http://www.cnblogs.com/coldplayerest/archive/2010/02/20/1669949.html