free
Role:
Linux as Free command displays memory status.
free command displays memory usage, including physical memory, virtual memory swap files, shared memory segments, core and buffer systems used.
format
free parameters [options]
If no arguments situation, "free" command displays memory usage information. According to the default statistics counts k (b) a.
[root@linus ~]# free
total used free shared buff/cache available
Mem: 1867048 314712 1090716 9356 461620 1338224
Swap: 2097148 0 2097148
In which the explanation:
Mem: Memory
Swap: Swap
total: represents the total size of physical memory. (Total = Used + as Free)
Used: indicates how many have been used.
free: indicates how many available memory.
Shared: represents the total amount of memory shared by multiple processes.
Buffers / cached: indicates the disk cache size
available: remaining available memory
In linux, you can use the View command options man manual, so -help option, for example to -help
[root@linus ~]# free --help
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
-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
-w, --wide wide output
--help display this help and exit
-V, --version output version information and exit
For more details see free(1).
Common options
-b: Byte units to display memory usage.
-k: in KB display memory usage.
-m: in MB display memory usage.
-g: in GB display content usage.
-h: displays memory usage in appropriate units, choose the most appropriate units (byte, kb, mb, gb , tb) in.
-l: show the level of memory utilization.
-t: Show all memory of linux.
-s N: N indicates seconds every time printing information memory until the end with ctrl + c ctrl + Z or suspended.
-c N: represents a repeating print information memory N times
-V: Display version information
Simple application
[root@linus ~]# free -k #以Byte为单位显示内存使用信息
total used free shared buff/cache available
Mem: 1867048 314204 1091164 9356 461680 1338684
Swap: 2097148 0 2097148
[root@linus ~]# free -b #以KB为单位显示内存使用情况
total used free shared buff/cache available
Mem: 1911857152 321617920 1117478912 9580544 472760320 1370939392
Swap: 2147479552 0 2147479552
[root@linus ~]# free -m #以MB为单位显示内存使用情况
total used free shared buff/cache available
Mem: 1823 306 1065 9 450 1307
Swap: 2047 0 2047
[root@linus ~]# free -h #以合适的单位显示内存使用情况
total used free shared buff/cache available
Mem: 1.8G 306M 1.0G 9.1M 450M 1.3G
Swap: 2.0G 0B 2.0G
[root@linus ~]# free -l #显示高低内存的利用率
total used free shared buff/cache available
Mem: 1867048 314456 1090900 9356 461692 1338432
Low: 1867048 776148 1090900
High: 0 0 0
Swap: 2097148 0 2097148
[root@linus ~]# free -t #显示linux的全部内存
total used free shared buff/cache available
Mem: 1867048 314300 1091040 9356 461708 1338572
Swap: 2097148 0 2097148
Total: 3964196 314300 3188188
[root@linus ~]# free -s 1 #每隔1秒打印一次内存信息，打印了四次之后，将进程挂起
total used free shared buff/cache available
Mem: 1867048 314828 1090512 9356 461708 1338044
Swap: 2097148 0 2097148
total used free shared buff/cache available
Mem: 1867048 314844 1090496 9356 461708 1338028
Swap: 2097148 0 2097148
total used free shared buff/cache available
Mem: 1867048 314844 1090496 9356 461708 1338028
Swap: 2097148 0 2097148
total used free shared buff/cache available
Mem: 1867048 314844 1090496 9356 461708 1338028
Swap: 2097148 0 2097148
^Z
[8]+ 已停止 free -s 1
[root@linus ~]# free -c 2 #打印内存信息两次
total used free shared buff/cache available
Mem: 1867048 315712 1089636 9356 461700 1337168
Swap: 2097148 0 2097148
total used free shared buff/cache available
Mem: 1867048 315712 1089636 9356 461700 1337168
Swap: 2097148 0 2097148
There are some remaining combinations, eg:
[root@linus ~]# free -h -s 2 -c 2 #以适合的单位打印，每隔两秒打印一次，共两次
total used free shared buff/cache available
Mem: 1.8G 308M 1.0G 9.1M 450M 1.3G
Swap: 2.0G 0B 2.0G
total used free shared buff/cache available
Mem: 1.8G 308M 1.0G 9.1M 450M 1.3G
Swap: 2.0G 0B 2.0G
