1.md5sum命令
“md5sum”就是计算和检验MD5信息签名。md5 checksum(通常叫做哈希)使用匹配或者验证文件的文件的完整性，因为文件可能因为传输错误，磁盘错误或者无恶意的干扰等原因而发生改变。
root@tecmint:~# md5sum teamviewer_linux.deb 47790ed345a7b7970fc1f2ac50c97002 teamviewer_linux.deb
注意：用户可以使用官方提供的和md5sum生成签名信息匹对以此检测文件是否改变。Md5sum没有sha1sum安全，这点我们稍后讨论。
2.“tar”命令是磁带归档(Tape Archive)，对创建一些文件的的归档和它们的解压很有用。
root@tecmint:~# tar -zxvf abc.tar.gz (记住'z'代表了.tar.gz) root@tecmint:~# tar -jxvf abc.tar.bz2 (记住'j'代表了.tar.bz2) root@tecmint:~# tar -cvf archieve.tar.gz(.bz2) /path/to/folder/abc
注意： “tar.gz“代表了使用gzip归档，“bar.bz2”使用bzip压缩的，它压缩的更好但是也更慢。
3.命令: Find
搜索指定目录下的文件，从开始于父目录，然后搜索子目录。
root@tecmint:~# find -name *.sh ./Desktop/load.sh ./Desktop/test.sh ./Desktop/shutdown.sh ./Binary/firefox/run-mozilla.sh ./Downloads/kdewebdev-3.5.8/quanta/scripts/externalpreview.sh ./Downloads/kdewebdev-3.5.8/admin/doxygen.sh ./Downloads/kdewebdev-3.5.8/admin/cvs.sh ./Downloads/kdewebdev-3.5.8/admin/ltmain.sh ./Downloads/wheezy-nv-install.sh
注意： `-name‘选项是搜索大小写敏感。可以使用`-iname‘选项，这样在搜索中可以忽略大小写。（*是通配符，可以搜索所有的文件；‘.sh‘你可以使用文件名或者文件名的一部分来制定输出结果）
4.命令: service
‘service‘命令控制服务的启动、停止和重启，它让你能够不重启整个系统就可以让配置生效以开启、停止或者重启某个服务。
在Ubuntu上启动apache2 server：
root@tecmint:~# service apache2 start * Starting web server apache2 apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName httpd (pid 1285) already running [ OK ]
5.命令: df
报告系统的磁盘使用情况。在跟踪磁盘使用情况方面对于普通用户和系统管理员都很有用。 ‘df‘ 通过检查目录大小工作，但这一数值仅当文件关闭时才得到更新。
root@tecmint:~# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 47929224 7811908 37675948 18% / none 4 0 4 0% /sys/fs/cgroup udev 1005916 4 1005912 1% /dev tmpfs 202824 816 202008 1% /run none 5120 0 5120 0% /run/lock none 1014120 628 1013492 1% /run/shm none 102400 44 102356 1% /run/user /dev/sda5 184307 79852 94727 46% /boot /dev/sda7 95989516 61104 91045676 1% /data /dev/sda8 91953192 57032 87218528 1% /personal
6.命令: du
估计文件的空间占用。 逐层统计文件（例如以递归方式）并输出摘要。
root@tecmint:~# du 8 ./Daily Pics/wp-polls/images/default_gradient 8 ./Daily Pics/wp-polls/images/default 32 ./Daily Pics/wp-polls/images 8 ./Daily Pics/wp-polls/tinymce/plugins/polls/langs 8 ./Daily Pics/wp-polls/tinymce/plugins/polls/img 28 ./Daily Pics/wp-polls/tinymce/plugins/polls 32 ./Daily Pics/wp-polls/tinymce/plugins 36 ./Daily Pics/wp-polls/tinymce 580 ./Daily Pics/wp-polls 1456 ./Daily Pics 36 ./Plugins/wordpress-author-box 16180 ./Plugins 12 ./May Articles 2013/Xtreme Download Manager 4632 ./May Articles 2013/XCache
注意: ‘df‘ 只显示文件系统的使用统计，但‘du‘统计目录内容。‘du‘命令的更详细信息请参
7.命令: ifconfig
ifconfig用来配置常驻内核的网络接口信息。在系统启动必要时用来设置网络适配器的信息。之后，它通常是只需要在调试时或当系统需要调整时使用。
检查活动网络适配器
[avishek@tecmint ~]$ ifconfig
eth0 Link encap:Ethernet HWaddr 40:2C:F4:EA:CF:0E
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:154389832 (147.2 MiB) TX bytes:65085817 (62.0 MiB)
Interrupt:20 Memory:f7100000-f7120000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4186 (4.0 KiB) TX bytes:4186 (4.0 KiB)
检查所有的网络适配器
“-a”参数用来显示所有网络适配器(网卡)的详细信息,包括那些停用的适配器。
[avishek@tecmint ~]$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 40:2C:F4:EA:CF:0E
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:154389832 (147.2 MiB) TX bytes:65085817 (62.0 MiB)
Interrupt:20 Memory:f7100000-f7120000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4186 (4.0 KiB) TX bytes:4186 (4.0 KiB)
virbr0 Link encap:Ethernet HWaddr 0e:30:a3:3a:bf:03
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
停用网络适配器
[avishek@tecmint ~]$ ifconfig eth0 down
启用网络适配器
[avishek@tecmint ~]$ ifconfig eth0 up
指定IP地址到网络适配器
为网络适配器eth0设定IP地址“192.168.1.12”.
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12
更改网络适配器eth0的子网掩码
[avishek@tecmint ~]$ ifconfig eth0 netmask 255.255.255.
更改网络适配器eth0的广播地址
[avishek@tecmint ~]$ ifconfig eth0 broadcast 192.168.1.255
为网络适配器eth0指定IP地址,子网掩码，广播地址
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12 netmask 255.255.255.0 broadcast 192.168.1.255
8.命令: netstat
netstat命令显示各种网络相关的信息，如网络连接,路由表,接口统计,伪装连接,组播成员身份等….
列出所有的网络端口
[avishek@tecmint ~]$ netstat -a
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 741379 /run/user/user1/keyring-I5cn1c/gpg
unix 2 [ ACC ] STREAM LISTENING 8965 /var/run/acpid.socket
unix 2 [ ACC ] STREAM LISTENING 18584 /tmp/.X11-unix/X0
unix 2 [ ACC ] STREAM LISTENING 741385 /run/user/user1/keyring-I5cn1c/ssh
unix 2 [ ACC ] STREAM LISTENING 741387 /run/user/user1/keyring-I5cn1c/pkcs11
unix 2 [ ACC ] STREAM LISTENING 20242 @/tmp/dbus-ghtTjuPN46
unix 2 [ ACC ] STREAM LISTENING 13332 /var/run/samba/winbindd_privileged/pipe
unix 2 [ ACC ] STREAM LISTENING 13331 /tmp/.winbindd/pipe
unix 2 [ ACC ] STREAM LISTENING 11030 /var/run/mysqld/mysqld.sock
unix 2 [ ACC ] STREAM LISTENING 19308 /tmp/ssh-qnZadSgJAbqd/agent.3221
unix 2 [ ACC ] STREAM LISTENING 436781 /tmp/HotShots
unix 2 [ ACC ] STREAM LISTENING 46110 /run/user/ravisaive/pulse/native
unix 2 [ ACC ] STREAM LISTENING 19310 /tmp/gpg-zfE9YT/S.gpg-agent
....
显示所有tcp相关端口
[avishek@tecmint ~]$ netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 localhost:mysql *:* LISTEN
tcp 0 0 *:5901 *:* LISTEN
tcp 0 0 *:5902 *:* LISTEN
tcp 0 0 *:x11-1 *:* LISTEN
tcp 0 0 *:x11-2 *:* LISTEN
tcp 0 0 *:5938 *:* LISTEN
tcp 0 0 localhost:5940 *:* LISTEN
tcp 0 0 ravisaive-OptiPl:domain *:* LISTEN
tcp 0 0 ravisaive-OptiPl:domain *:* LISTEN
tcp 0 0 localhost:ipp *:* LISTEN
tcp 0 0 ravisaive-OptiPle:48270 ec2-23-21-236-70.c:http ESTABLISHED
tcp 0 0 ravisaive-OptiPle:48272 ec2-23-21-236-70.c:http TIME_WAIT
tcp 0 0 ravisaive-OptiPle:48421 bom03s01-in-f22.1:https ESTABLISHED
tcp 0 0 ravisaive-OptiPle:48269 ec2-23-21-236-70.c:http ESTABLISHED
tcp 0 0 ravisaive-OptiPle:39084 channel-ecmp-06-f:https ESTABLISHED
...
显示所有连接的统计信息
[avishek@tecmint ~]$ netstat -s
Ip:
4994239 total packets received
0 forwarded
0 incoming packets discarded
4165741 incoming packets delivered
3248924 requests sent out
8 outgoing packets dropped
Icmp:
29460 ICMP messages received
566 input ICMP message failed.
ICMP input histogram:
destination unreachable: 98
redirects: 29362
2918 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 2918
IcmpMsg:
InType3: 98
InType5: 29362
OutType3: 2918
Tcp:
94533 active connections openings
23 passive connection openings
5870 failed connection attempts
7194 connection resets received
....
好的！由于某些原因如果你不想解析netstat 输出的主机、端口和用户名称的话 。
[avishek@tecmint ~]$ netstat -an
好，你可能需要获取的 netstat 持续输出的动态信息，通过传递中断输出指令 (ctrl + c)来停止。
[avishek@tecmint ~]$ netstat -c
9.命令: netstat
netstat命令显示各种网络相关的信息，如网络连接,路由表,接口统计,伪装连接,组播成员身份等….
列出所有的网络端口
[avishek@tecmint ~]$ netstat -a
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 741379 /run/user/user1/keyring-I5cn1c/gpg
unix 2 [ ACC ] STREAM LISTENING 8965 /var/run/acpid.socket
unix 2 [ ACC ] STREAM LISTENING 18584 /tmp/.X11-unix/X0
unix 2 [ ACC ] STREAM LISTENING 741385 /run/user/user1/keyring-I5cn1c/ssh
unix 2 [ ACC ] STREAM LISTENING 741387 /run/user/user1/keyring-I5cn1c/pkcs11
unix 2 [ ACC ] STREAM LISTENING 20242 @/tmp/dbus-ghtTjuPN46
unix 2 [ ACC ] STREAM LISTENING 13332 /var/run/samba/winbindd_privileged/pipe
unix 2 [ ACC ] STREAM LISTENING 13331 /tmp/.winbindd/pipe
unix 2 [ ACC ] STREAM LISTENING 11030 /var/run/mysqld/mysqld.sock
unix 2 [ ACC ] STREAM LISTENING 19308 /tmp/ssh-qnZadSgJAbqd/agent.3221
unix 2 [ ACC ] STREAM LISTENING 436781 /tmp/HotShots
unix 2 [ ACC ] STREAM LISTENING 46110 /run/user/ravisaive/pulse/native
unix 2 [ ACC ] STREAM LISTENING 19310 /tmp/gpg-zfE9YT/S.gpg-agent
....
显示所有tcp相关端口
[avishek@tecmint ~]$ netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 localhost:mysql *:* LISTEN
tcp 0 0 *:5901 *:* LISTEN
tcp 0 0 *:5902 *:* LISTEN
tcp 0 0 *:x11-1 *:* LISTEN
tcp 0 0 *:x11-2 *:* LISTEN
tcp 0 0 *:5938 *:* LISTEN
tcp 0 0 localhost:5940 *:* LISTEN
tcp 0 0 ravisaive-OptiPl:domain *:* LISTEN
tcp 0 0 ravisaive-OptiPl:domain *:* LISTEN
tcp 0 0 localhost:ipp *:* LISTEN
tcp 0 0 ravisaive-OptiPle:48270 ec2-23-21-236-70.c:http ESTABLISHED
tcp 0 0 ravisaive-OptiPle:48272 ec2-23-21-236-70.c:http TIME_WAIT
tcp 0 0 ravisaive-OptiPle:48421 bom03s01-in-f22.1:https ESTABLISHED
tcp 0 0 ravisaive-OptiPle:48269 ec2-23-21-236-70.c:http ESTABLISHED
tcp 0 0 ravisaive-OptiPle:39084 channel-ecmp-06-f:https ESTABLISHED
...
显示所有连接的统计信息
[avishek@tecmint ~]$ netstat -s
Ip:
4994239 total packets received
0 forwarded
0 incoming packets discarded
4165741 incoming packets delivered
3248924 requests sent out
8 outgoing packets dropped
Icmp:
29460 ICMP messages received
566 input ICMP message failed.
ICMP input histogram:
destination unreachable: 98
redirects: 29362
2918 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 2918
IcmpMsg:
InType3: 98
InType5: 29362
OutType3: 2918
Tcp:
94533 active connections openings
23 passive connection openings
5870 failed connection attempts
7194 connection resets received
....
好的！由于某些原因如果你不想解析netstat 输出的主机、端口和用户名称的话 。
[avishek@tecmint ~]$ netstat -an
好，你可能需要获取的 netstat 持续输出的动态信息，通过传递中断输出指令 (ctrl + c)来停止。
[avishek@tecmint ~]$ netstat -c
10.命令： nslookup
网络实用程序，用于获得互联网服务器的信息。顾名思义，该实用程序将发现通过查询 DNS 域的名称服务器信息。
[avishek@tecmint ~]$ nslookup tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
Name: tecmint.com
Address: 50.16.67.239
查询邮件交换器记录
[avishek@tecmint ~]$ nslookup -query=mx tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
tecmint.com mail exchanger = 0 smtp.secureserver.net.
tecmint.com mail exchanger = 10 mailstore1.secureserver.net.
Authoritative answers can be found from:
查询域名服务器
[avishek@tecmint ~]$ nslookup -type=ns tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
tecmint.com nameserver = ns3404.com.
tecmint.com nameserver = ns3403.com.
Authoritative answers can be found from:
查询DNS记录
[avishek@tecmint ~]$ nslookup -type=any tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
tecmint.com mail exchanger = 10 mailstore1.secureserver.net.
tecmint.com mail exchanger = 0 smtp.secureserver.net.
tecmint.com nameserver = ns06.domaincontrol.com.
tecmint.com nameserver = ns3404.com.
tecmint.com nameserver = ns3403.com.
tecmint.com nameserver = ns05.domaincontrol.com.
Authoritative answers can be found from:
查询起始授权机构
[avishek@tecmint ~]$ nslookup -type=soa tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
tecmint.com
origin = ns3403.hostgator.com
mail addr = dnsadmin.gator1702.hostgator.com
serial = 2012081102
refresh = 86400
retry = 7200
expire = 3600000
minimum = 86400
Authoritative answers can be found from:
查询端口号
更改使用你想要连接的端口号
[avishek@tecmint ~]$ nslookup -port 56 tecmint.com
Server: tecmint.com
Address: 50.16.76.239#53
Name: 56
Address: 14.13.253.12
11.命令: dig
dig是查询DNS 域名服务器的工具，可以查询的主机地址、 邮件交流、 域名服务器相关的信息。在任何 Linux (Unix) 或 Macintosh OS X 操作系统上，都可以使用该工具。dig的最典型的用法是单个主机的查询。
[avishek@tecmint ~]$ dig tecmint.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER< 关闭注释行 [avishek@tecmint ~]$ dig tecmint.com +nocomments ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +nocomments ;; global options: +cmd ;tecmint.com. IN A tecmint.com. 14400 IN A 40.216.66.239 ;; Query time: 418 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Sat Jun 29 13:53:22 2013 ;; MSG SIZE rcvd: 45 关闭认证块 [avishek@tecmint ~]$ dig tecmint.com +noauthority ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +noauthority ;; global options: +cmd ;; Got answer: ;; ->>HEADER< 关闭 其他 块 [avishek@tecmint ~]$ dig tecmint.com +noadditional ; <<>> DiG 9.9.2-P1 <<>> tecmint.com +noadditional ;; global options: +cmd ;; Got answer: ;; ->>HEADER< 关闭 统计块 [avishek@tecmint ~]$ dig tecmint.com +nostats ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +nostats ;; global options: +cmd ;; Got answer: ;; ->>HEADER< 关闭回复块 [avishek@tecmint ~]$ dig tecmint.com +noanswer ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +noanswer ;; global options: +cmd ;; Got answer: ;; ->>HEADER< 关闭所有块 [avishek@tecmint ~]$ dig tecmint.com +noall ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +noall ;; global options: +cmd
12.命令：w 它是一个命令，尽管只有一个字符长！命令”w“是uptime和who命令，以前后的顺序组合在一起。
[avishek@tecmint ~]$ w 15:05:42 up 4:49, 3 users, load average: 0.02, 0.01, 0.00 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT server tty7 :0 14:06 4:43m 1:42 0.08s pam: gdm-passwo server pts/0 :0.0 14:18 0.00s 0.23s 1.65s gnome-terminal server pts/1 :0.0 14:47 4:43 0.01s 0.01s bash
13.lsof 命令
lsof 是”list open files(“列表中打开的文件”) 的缩写，显示您的系统当前已打开的所有文件。这是非常有用的对于想找出哪些进程使用某一特定文件，或显示为单个进程打开所有文件。一些有用的10 个lsof 命令示例，你可能会感兴趣阅读。
[avishek@tecmint ~]$ lsof COMMAND PID TID USER FD TYPE DEVICE SIZE/OFF NODE NAME init 1 root cwd DIR 8,1 4096 2 / init 1 root rtd DIR 8,1 4096 2 / init 1 root txt REG 8,1 227432 395571 /sbin/init init 1 root mem REG 8,1 47080 263023 /lib/i386-linux-gnu/libnss_files-2.17.so init 1 root mem REG 8,1 42672 270178 /lib/i386-linux-gnu/libnss_nis-2.17.so init 1 root mem REG 8,1 87940 270187 /lib/i386-linux-gnu/libnsl-2.17.so init 1 root mem REG 8,1 30560 263021 /lib/i386-linux-gnu/libnss_compat-2.17.so init 1 root mem REG 8,1 124637 270176 /lib/i386-linux-gnu/libpthread-2.17.so init 1 root mem REG 8,1 1770984 266166 /lib/i386-linux-gnu/libc-2.17.so init 1 root mem REG 8,1 30696 262824 /lib/i386-linux-gnu/librt-2.17.so init 1 root mem REG 8,1 34392 262867 /lib/i386-linux-gnu/libjson.so.0.1.0 init 1 root mem REG 8,1 296792 262889 /lib/i386-linux-gnu/libdbus-1.so.3.7.2 init 1 root mem REG 8,1 34168 262840 /lib/i386-linux-gnu/libnih-dbus.so.1.0.0 init 1 root mem REG 8,1 95616 262848 /lib/i386-linux-gnu/libnih.so.1.0.0 init 1 root mem REG 8,1 134376 270186 /lib/i386-linux-gnu/ld-2.17.so init 1 root 0u CHR 1,3 0t0 1035 /dev/null init 1 root 1u CHR 1,3 0t0 1035 /dev/null init 1 root 2u CHR 1,3 0t0 1035 /dev/null init 1 root 3r FIFO 0,8 0t0 1714 pipe init 1 root 4w FIFO 0,8 0t0 1714 pipe init 1 root 5r 0000 0,9 0 6245 anon_inode init 1 root 6r 0000 0,9 0 6245 anon_inode init 1 root 7u unix 0xf5e91f80 0t0 8192 @/com/ubuntu/upstart init 1 root 8w REG 8,1 3916 39
14.命令: free
跟踪内存的使用和资源一样重要，就像管理员执行的任何其它任务，可以使用 ‘free’ 命令来在这里救援.
当前内存使用状态Current Usage Status of Memory
[avishek@tecmint ~]$ free
total used free shared buffers cached
Mem: 2028240 1788272 239968 0 69468 363716
-/+ buffers/cache: 1355088 673152
Swap: 3905532 157076 3748456
设置输出单位为KB，MB或GB
[avishek@tecmint ~]$ free -b
total used free shared buffers cached
Mem: 2076917760 1838272512 238645248 0 71348224 372670464
-/+ buffers/cache: 1394253824 682663936
Swap: 3999264768 160845824 3838418944
[avishek@tecmint ~]$ free -k
total used free shared buffers cached
Mem: 2028240 1801484 226756 0 69948 363704
-/+ buffers/cache: 1367832 660408
Swap: 3905532 157076 3748456
[avishek@tecmint ~]$ free -m
total used free shared buffers cached
Mem: 1980 1762 218 0 68 355
-/+ buffers/cache: 1338 641
Swap: 3813 153 3660
[avishek@tecmint ~]$ free -g
total used free shared buffers cached
Mem: 1 1 0 0 0 0
-/+ buffers/cache: 1 0
Swap: 3 0 3
以可读的格式显示，检查当前内存使用
[avishek@tecmint ~]$ free -h
total used free shared buffers cached
Mem: 1.9G 1.7G 208M 0B 68M 355M
-/+ buffers/cache: 1.3G 632M
Swap: 3.7G 153M 3.6G
设定时间间隔后，持续检查使用状态
[avishek@tecmint ~]$ free -s 3
total used free shared buffers cached
Mem: 2028240 1824096 204144 0 70708 364180
-/+ buffers/cache: 1389208 639032
Swap: 3905532 157076 3748456
total used free shared buffers cached
Mem: 2028240 1824192 204048 0 70716 364212
-/+ buffers/cache: 1389264 638976
Swap: 3905532 157076 3748456
