Mac使用系统监控命令vmstat提示下面错误：
chandler@ChandlerdeMacBook-Pro ~ % vmstat -v
zsh: command not found: vmstat
因为Mac使用的是vm_stat，特别记录一下：
chandler@ChandlerdeMacBook-Pro ~ % vm_stat
Mach Virtual Memory Statistics: (page size of 4096 bytes)
Pages free: 111180.
Pages active: 1519593.
Pages inactive: 1477754.
Pages speculative: 40760.
Pages throttled: 0.
Pages wired down: 767152.
Pages purgeable: 586692.
"Translation faults": 362914033.
Pages copy-on-write: 9314765.
Pages zero filled: 286680579.
Pages reactivated: 5825270.
Pages purged: 1986983.
File-backed pages: 600641.
Anonymous pages: 2437466.
Pages stored in compressor: 984663.
Pages occupied by compressor: 277410.
Decompressions: 5580331.
Compressions: 11668507.
Pageins: 8050564.
Pageouts: 46283.
Swapins: 2288375.
Swapouts: 2383825.
