Linux 系统管理命令之 free 命令

free 命令

功能：显示内存状态
free 指令会显示内存的使用情况，包括实体内存，虚拟的交换文件内存，共享内存区段，以及系统核心使用的缓冲区等；

语法

free [-bkmghotV][-s <间隔秒数>][-c <显示次数>]

参数说明

1. -b 以 Byte 为单位显示内存使用情况
2. -k 以 KB 为单位显示内存使用情况
3. -m 以 MB 为单位显示内存使用情况
4. -o 不显示缓冲区调节列
5. -s <间隔秒数> 持续观察内存使用状况
6. -t 显示内存总和列
7. -V 显示版本信息
8. -h 以合适的单位显示

用法如下：

Usage:
 free [options]

Options:
 -b, --bytes         show output in bytes
 -k, --kilo          show output in kilobytes
 -m, --mega          show output in megabytes
 -g, --giga          show output in gigabytes
     --tera          show output in terabytes
 -h, --human         show human-readable output
     --si            use powers of 1000 not 1024
 -l, --lohi          show detailed low and high memory statistics
 -o, --old           use old format (without -/+buffers/cache line)
 -t, --total         show total for RAM + swap
 -s N, --seconds N   repeat printing every N seconds
 -c N, --count N     repeat printing N times, then exit

     --help     display this help and exit
 -V, --version  output version information and exit

For more details see free(1).

举例说明

qieg@work-vm:~$ free
             total       used       free     shared    buffers     cached
Mem:       1024664     921656     103008       2152     163292     254788
-/+ buffers/cache:     503576     521088
Swap:      3176444      21364    3155080
qieg@work-vm:~$ free -b
             total       used       free     shared    buffers     cached
Mem:    1049255936  943775744  105480192    2203648  167211008  260902912
-/+ buffers/cache:  515661824  533594112
Swap:   3252678656   21876736 3230801920
qieg@work-vm:~$ free -k
             total       used       free     shared    buffers     cached
Mem:       1024664     921644     103020       2152     163300     254788
-/+ buffers/cache:     503556     521108
Swap:      3176444      21364    3155080
qieg@work-vm:~$ free -m
             total       used       free     shared    buffers     cached
Mem:          1000        900        100          2        159        248
-/+ buffers/cache:        491        508
Swap:         3101         20       3081

qieg@work-vm:~$ free -h
             total       used       free     shared    buffers     cached
Mem:          1.0G       886M       114M       2.1M       159M       248M
-/+ buffers/cache:       477M       522M
Swap:         3.0G        20M       3.0G
qieg@work-vm:~$ free -s 1
             total       used       free     shared    buffers     cached
Mem:       1024664     907764     116900       2180     163484     254868
-/+ buffers/cache:     489412     535252
Swap:      3176444      21364    3155080

             total       used       free     shared    buffers     cached
Mem:       1024664     907776     116888       2180     163484     254868
-/+ buffers/cache:     489424     535240
Swap:      3176444      21364    3155080

             total       used       free     shared    buffers     cached
Mem:       1024664     907772     116892       2180     163484     254868
-/+ buffers/cache:     489420     535244
Swap:      3176444      21364    3155080


qieg@work-vm:~$ free -h -c3
             total       used       free     shared    buffers     cached
Mem:          1.0G       887M       112M       2.1M       159M       250M
-/+ buffers/cache:       477M       522M
Swap:         3.0G        20M       3.0G

             total       used       free     shared    buffers     cached
Mem:          1.0G       888M       112M       2.1M       159M       250M
-/+ buffers/cache:       478M       522M
Swap:         3.0G        20M       3.0G

             total       used       free     shared    buffers     cached
Mem:          1.0G       888M       112M       2.1M       159M       250M
-/+ buffers/cache:       478M       522M
Swap:         3.0G        20M       3.0G

finger 命令

功能：查找并显示用户信息
语法：finger [-lmsp][帐号名称…]

qieg@work-vm:~$ finger -l -m -s command
Login: command                  Name: command list
Directory: /home                Shell: /bin/bash
Never logged in.
No mail.
No Plan.