Linux - 常用Linux命令详解 - 《KCA-KCP》

lscpu
df
free
ifconfig
ip
定时任务
软链接

[root@localhost ~]$ hostname
localhost.localdomain
[root@localhost ~]$ 
[root@localhost ~]$ cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
[root@localhost ~]$ 
[root@localhost ~]$

lscpu

lscpu命令从sysfs和/proc/cpuinfo收集cpu体系结构信息，命令的输出比较易读，命令输出的信息包含cpu数量，线程，核数，套接字等。

[root@localhost ~]$ cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core) 
[root@localhost ~]$ 
[root@localhost ~]$ uname -a
Linux localhost.localdomain 3.10.0-327.el7.x86_64 #1 SMP Thu Nov 19 22:10:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]$ 
[root@localhost ~]$

[root@localhost ~]$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    2
座：                 2
NUMA 节点：         1
厂商 ID：           AuthenticAMD
CPU 系列：          23
型号：              96
型号名称：        AMD Ryzen 7 4800U with Radeon Graphics
步进：              1
CPU MHz：             1796.624
BogoMIPS：            3593.24
超管理器厂商：  VMware
虚拟化类型：     完全
L1d 缓存：          32K
L1i 缓存：          32K
L2 缓存：           512K
L3 缓存：           4096K
NUMA 节点0 CPU：    0-3
[root@localhost ~]$

[root@localhost ~]$ cat /proc/cpuinfo | grep -i processor |wc -l
4
[root@localhost ~]$ cat /proc/meminfo | grep -i memtotal
MemTotal:        4031812 kB
[root@localhost ~]$ 
[root@localhost ~]$ cat /proc/meminfo | grep -i swaptotal
SwapTotal:       3907580 kB
[root@localhost ~]$ 
[root@localhost ~]$

df

[roote@localhost ~]$ df -hT
文件系统                类型      容量  已用  可用 已用% 挂载点
/dev/mapper/centos-root xfs        19G  7.1G   12G   38% /
devtmpfs                devtmpfs  2.0G     0  2.0G    0% /dev
tmpfs                   tmpfs     2.0G  164K  2.0G    1% /dev/shm
tmpfs                   tmpfs     2.0G  9.0M  2.0G    1% /run
tmpfs                   tmpfs     2.0G     0  2.0G    0% /sys/fs/cgroup
/dev/mapper/centos-home xfs        19G  874M   18G    5% /home
/dev/sda1               xfs       473M  140M  334M   30% /boot
tmpfs                   tmpfs     394M  8.0K  394M    1% /run/user/1001
[root@localhost ~]$

lsblk命令的英文是“list block”，即用于列出所有可用块设备的信息，而且还能显示他们之间的依赖关系，但是它不会列出RAM盘的信息。

[root@localhost ~]$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   50G  0 disk 
├─sda1            8:1    0  476M  0 part /boot
└─sda2            8:2    0   41G  0 part 
  ├─centos-root 253:0    0 18.6G  0 lvm  /
  ├─centos-swap 253:1    0  3.7G  0 lvm  [SWAP]
  └─centos-home 253:2    0 18.6G  0 lvm  /home
sr0              11:0    1 1024M  0 rom  
[root@localhost ~]$ 
[root@localhost ~]# lsblk -f            //显示文件系统信息
NAME            FSTYPE      LABEL UUID                                   MOUNTPOINT
sda                                                                      
├─sda1          xfs               5b427b21-cc9e-4d0b-8582-05a58167b2e2   /boot
└─sda2          LVM2_member       DcVwt2-k1rH-0N1I-VW5v-K8tI-dp1c-rqIMwF 
  ├─centos-root xfs               2bead122-3654-428f-84ec-cca4b9aa58d6   /
  ├─centos-swap swap              5b1c047e-656a-4ba8-a4f5-0587b894ae75   [SWAP]
  └─centos-home xfs               f11952af-6dac-482c-9e62-12d6846ef86d   /home
sr0                                                                      
[root@localhost ~]#

free

free 命令能够显示系统中物理上的空闲和已用内存，还有交换内存，同时，也能显示被内核使用的缓冲和缓存。这些信息是通过解析文件 /proc/meminfo 而收集到的。
不带任何选项运行 free 命令会显示系统内存，包括空闲、已用、交换、缓冲、缓存和交换的内存总数。
语法格式
free [参数]
常用参数：

-b	以Byte显示内存使用情况
-k	以kb为单位显示内存使用情况
-m	以mb为单位显示内存使用情况
-g	以gb为单位显示内存使用情况
-s	持续显示内存
-t	显示内存使用总合

[root@localhost ~]# free
              total        used        free      shared  buff/cache   available
Mem:        4031812      572364     2948844       71332      510604     3136248
Swap:       3907580           0     3907580
[root@localhost ~]# 
[root@localhost ~]# free -k
              total        used        free      shared  buff/cache   available
Mem:        4031812      572364     2948844       71332      510604     3136248
Swap:       3907580           0     3907580
[root@localhost ~]# 
[root@localhost ~]# free -m
              total        used        free      shared  buff/cache   available
Mem:           3937         559        2879          69         498        3062
Swap:          3815           0        3815
[root@localhost ~]# 
[root@localhost ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
[root@localhost ~]# 
[root@localhost ~]# free -t
              total        used        free      shared  buff/cache   available
Mem:        4031812      572760     2948448       71332      510604     3135852
Swap:       3907580           0     3907580
Total:      7939392      572760     6856028
[root@localhost ~]# 
[root@localhost ~]# free -t -g
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
Total:            7           0           6
[root@localhost ~]# 
[root@localhost ~]# free -g -t -s 3
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
Total:            7           0           6
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
Total:            7           0           6
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
Total:            7           0           6
              total        used        free      shared  buff/cache   available
Mem:              3           0           2           0           0           2
Swap:             3           0           3
Total:            7           0           6

ifconfig


[root@localhost ~]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.88  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::20c:29ff:fe46:a284  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:46:a2:84  txqueuelen 1000  (Ethernet)
        RX packets 543  bytes 48057 (46.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 324  bytes 51806 (50.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 488  bytes 42400 (41.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 488  bytes 42400 (41.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:21:27:5e  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
virbr0-nic: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether 52:54:00:21:27:5e  txqueuelen 500  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
[root@localhost ~]# 
[root@localhost ~]# 
[root@localhost ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:46:a2:84 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.88/24 brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe46:a284/64 scope link 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 500
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
[root@localhost ~]#

ip

[kingbase@localhost ~]$ ip -4 a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    inet 192.168.0.89/24 brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
[kingbase@localhost ~]$

[root@localhost ~]# ip -a
Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }
       ip [ -force ] -batch filename
where  OBJECT := { link | addr | addrlabel | route | rule | neigh | ntable |
                   tunnel | tuntap | maddr | mroute | mrule | monitor | xfrm |
                   netns | l2tp | tcp_metrics | token }
       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |
                    -h[uman-readable] | -iec |
                    -f[amily] { inet | inet6 | ipx | dnet | bridge | link } |
                    -4 | -6 | -I | -D | -B | -0 |
                    -l[oops] { maximum-addr-flush-attempts } |
                    -o[neline] | -t[imestamp] | -b[atch] [filename] |
                    -rc[vbuf] [size] | -n[etns] name | -a[ll] }
[root@localhost ~]# 
[root@localhost ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:dd:fc:e9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.89/24 brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fedd:fce9/64 scope link 
       valid_lft forever preferred_lft forever
3: eno33554976: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
    link/ether 00:0c:29:dd:fc:f3 brd ff:ff:ff:ff:ff:ff
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
5: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 500
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# 
[root@localhost ~]# ip -4 a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    inet 192.168.0.89/24 brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
[root@localhost ~]# 
[root@localhost ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:46:a2:84 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.88/24 brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe46:a284/64 scope link 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 500
    link/ether 52:54:00:21:27:5e brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# 
[root@localhost ~]#

ps -ef | grep -i kingbase
ps -ef （-e 显示所有程序；-f 显示UID，PPID，C与STIME栏位）
grep -i （-i，忽略大小写）

[kingbase@localhost ~]$ ps -ef | grep -i kingbase
kingbase   1774      1  0 13:48 ?        00:00:00 /opt/Kingbase/ES/V8/Server/bin/kingbase -D /opt/Kingbase/ES/V8/data
kingbase   1851   1774  0 13:48 ?        00:00:00 kingbase: logger   
kingbase   1860   1774  0 13:48 ?        00:00:00 kingbase: checkpointer   
kingbase   1861   1774  0 13:48 ?        00:00:00 kingbase: background writer   
kingbase   1862   1774  0 13:48 ?        00:00:00 kingbase: walwriter   
kingbase   1863   1774  0 13:48 ?        00:00:00 kingbase: autovacuum launcher   
kingbase   1864   1774  0 13:48 ?        00:00:00 kingbase: stats collector   
kingbase   1865   1774  0 13:48 ?        00:00:00 kingbase: ksh writer   
kingbase   1866   1774  0 13:48 ?        00:00:00 kingbase: ksh collector   
kingbase   1867   1774  0 13:48 ?        00:00:00 kingbase: kwr collector   
kingbase   1868   1774  0 13:48 ?        00:00:00 kingbase: logical replication launcher

[root@localhost ~]# systemctl status firewalld.service 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since 三 2021-12-15 13:48:32 CST; 19min ago
 Main PID: 955 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─955 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
12月 15 21:41:31 localhost.localdomain systemd[1]: Starting firewalld - dyna...
12月 15 13:48:32 localhost.localdomain systemd[1]: Started firewalld - dynam...
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# 
[root@localhost ~]# systemctl stop firewalld.service 
[root@localhost ~]# 
[root@localhost ~]# systemctl disable firewalld.service 
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.
[root@localhost ~]# 
[root@localhost ~]# systemctl status firewalld.service 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
12月 15 21:41:31 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
12月 15 13:48:32 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
12月 15 14:08:10 localhost.localdomain systemd[1]: Stopping firewalld - dynamic firewall daemon...
12月 15 14:08:11 localhost.localdomain systemd[1]: Stopped firewalld - dynamic firewall daemon.
[root@localhost ~]#

定时任务

启动或关闭

由于Cron 是Linux的内置服务，可以用以下的方法启动、关闭这个服务:
/sbin/service crond start //启动服务 /sbin/service crond stop //关闭服务 /sbin/service crond restart //重启服务 /sbin/service crond reload //重新载入配置

cron任务文件

cron 会从如下这些地方读取安装的任务：

/etc/anacrontab
这个文件存着系统级的任务。它主要用来运行每日的(daily)，每周的(weekly),每月的(monthly)的任务。一般不在此文件安装自己的任务
/etc/cron.d/
此目录下存放的是系统级任务的任务文件
/var/spool/cron/
此目录下存放各个用户的任务文件。各个用户的任务存放在以自已用户名为文件名的任务文件中。此文件中的指令行没有用户域。
新任务安装后或任务修改后不需要重启cron进程即可生效。

日志文件

可以通过查看文件/var/log/cron查看任务的运行情况。

软链接

[root@localhost V8]# ln -s /data /opt/Kingbase/ES/V8/data 
[root@localhost V8]# 
[root@localhost V8]# ls -al
总用量 84
drwxr-x--x. 15 kingbase kingbase  4096 3月  22 23:25 .
drwxr-xr-x.  3 root     root        15 12月 21 11:13 ..
drwxrwxr-x.  5 kingbase kingbase    38 12月 21 14:26 ClientTools
-rw-------.  1 kingbase kingbase   108 3月  20 21:28 control.so
lrwxrwxrwx.  1 root     root         5 3月  22 23:25 data -> /data
drwxr-x---.  2 kingbase kingbase  4096 12月 21 14:26 desktops
drwxrwxr-x.  7 kingbase kingbase  4096 3月   9 16:54 DtsTools
drwxrwxr-x.  2 kingbase kingbase  8192 12月 21 14:26 Help
drwxrwxr-x. 17 kingbase kingbase  4096 12月 21 14:26 Interface
drwxr-x---.  6 kingbase kingbase  4096 4月   1 2016 jre
drwxrwxr-x.  4 kingbase kingbase    30 3月   9 16:54 .kingbase
-rw-rw-r--.  1 kingbase kingbase  3386 3月  20 21:28 license.dat
-rwxr-x---.  1 kingbase kingbase  3386 12月 21 14:33 license.dat.old20220320
-rwxr-x---.  1 kingbase kingbase 11198 4月   9 2020 LICENSE_EN
-rwxr-x---.  1 kingbase kingbase 10366 4月   9 2020 LICENSE_ZH
drwxrwxr-x.  2 kingbase kingbase    57 12月 21 14:28 Logs
drwxrwxr-x.  9 kingbase kingbase  4096 3月   9 16:51 ManagerTools
drwxr-x---.  2 kingbase kingbase  4096 12月 21 14:27 Scripts
drwxrwxr-x.  5 kingbase kingbase    38 12月 21 14:26 Server
drwxr-x---.  5 kingbase kingbase  4096 12月 21 14:28 Uninstall
drwxrwxr-x.  6 kingbase kingbase  4096 12月 21 14:26 xulrunner