linux---网络相关配置，ssh服务，bash命令及优先级，元字符

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二：临时配置网络（ip，网关，dns）+永久配置
临时配置：

[root@nfs-server ~]#
ifconfig

ens32:
flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500

inet
192.168.152.134  netmask 255.255.255.0  broadcast 192.168.152.255

inet6
fe80::e33a:cec4:b0d4:c884  prefixlen 64  scopeid 0x20<link>

ether
00:0c:29:f7:dc:59  txqueuelen 1000  (Ethernet)

RX
packets 241828  bytes 275307222 (262.5 MiB)

RX
errors 0  dropped 0  overruns 0  frame 0

TX
packets 7200  bytes 1083100 (1.0 MiB)

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 1  (Local Loopback)

RX
packets 327  bytes 33260 (32.4 KiB)

RX
errors 0  dropped 0  overruns 0  frame 0

TX
packets 327  bytes 33260 (32.4 KiB)

TX
errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@nfs-server ~]#
ifconfig ens32 192.168.152.135

[root@nfs-server ~]# route
-n

Kernel IP routing table

Destination    
Gateway         Genmask       Flags
Metric Ref   Use Iface

192.168.152.0  
0.0.0.0        
255.255.255.0   U    
0      0        0
ens32

[root@nfs-server ~]# route
add default gw 192.168.152.2

[root@nfs-server ~]# route
-n

Kernel IP routing table

Destination    
Gateway         Genmask      
Flags Metric Ref  Use Iface

0.0.0.0        
192.168.152.2  
0.0.0.0         UG   
0      0        0
ens32

192.168.152.0  
0.0.0.0        
255.255.255.0   U    
0      0        0
ens32

[root@nfs-server ~]# cat
/etc/resolv.conf

# Generated by
NetworkManager

search localdomain

nameserver 192.168.152.2

nameserver 202.106.0.20

永久配置：

[root@nfs-server ~]# cat
/etc/sysconfig/network-scripts/ifcfg-ens32

TYPE=Ethernet

BOOTPROTO=dhcp

IPADDR=192.168.152.134

NETMASK=255.255.255.0

GATEWAY=192.168.152.2

DNS1=192.168.152.2

DNS2=202.106.0.20

DEFROUTE=yes

PEERDNS=yes

PEERROUTES=yes

IPV4_FAILURE_FATAL=no

IPV6INIT=yes

IPV6_AUTOCONF=yes

IPV6_DEFROUTE=yes

IPV6_PEERDNS=yes

IPV6_PEERROUTES=yes

IPV6_FAILURE_FATAL=no

IPV6_ADDR_GEN_MODE=stable-privacy

NAME=ens32

UUID=9eff3909-2614-4df9-80c9-a6a7d9f1be28

DEVICE=ens32

ONBOOT=yes

[root@nfs-server ~]#
systemctl restart network

三：为集群内的机器设定主机名，利用/etc/hosts文件来解析自己的集群中所有的主机名，相应的，集群的配置应该改成使用主机名的方式

修改主机名：
hostname python_web1
cat /etc/hostname 
python_web1
修改host文件:
[root@python_web1 ~]# cat /etc/hosts 
192.168.2.3 python_web1
[root@python_web1 ~]# ping python_web1

四：ssh登录，scp上传、下载，ssh秘钥登录，修改ssh
server端的端口为8888然后进行登录和scp测试
SSH登录：

[root@proxy-nfs ~]# scp
/etc/hosts web01:/tmp

The authenticity of
host 'web01 (192.168.152.135)' can't be established.

ECDSA key
fingerprint is 4c:ee:a3:f1:5c:37:43:32:bd:06:4e:cc:3f:5a:0a:04.

Are you sure you want
to continue connecting (yes/no)? yes

Warning: Permanently
added 'web01,192.168.152.135' (ECDSA) to the list of known hosts.

root@web01's password:

hosts                                                                    
100%  274     0.3KB/s  
00:00

[root@proxy-nfs ~]# scp
web01:/tmp/hosts .

root@web01's password:

hosts                                                                    
100%  274     0.3KB/s  
00:00

[root@proxy-nfs ~]# ls -l
hosts

-rw-r--r-- 1 root root 274
Mar 21 15:05 hosts

秘钥登录：

[root@proxy-nfs ~]#
ssh-keygen

Generating public/private rsa
key pair.

Enter
file in which to save the key (/root/.ssh/id_rsa):

Enter passphrase
(empty for no passphrase):

Enter same passphrase
again:

Your identification has
been saved in /root/.ssh/id_rsa.

Your public key
has been saved in /root/.ssh/id_rsa.pub.

The key
fingerprint is:

29:90:f7:3a:24:0a:e2:f9:22:ec:f4:07:75:7c:10:6b
root@proxy-nfs

The key's randomart
image is:

+--[ RSA 2048]----+

|      
..        |

|     .
..        |

|    o
oE.        |

|    
+.+ o       |

|o   o +
S        |

|o..o o
o         |

|.+. .
o          |

|ooo  .
.         |

|o..o.           
|

+-----------------+

[root@proxy-nfs ~]#
ssh-copy-id -i web01

/usr/bin/ssh-copy-id: INFO:
attempting to log in with the new key(s), to
filter out any that are already installed

/usr/bin/ssh-copy-id: INFO:
1 key(s) remain to be installed -- if you are prompted now
it is to install the new keys

root@web01's password:

Number of key(s) added: 1

Now try logging into the
machine, with:   "ssh 'web01'"

and check to make sure that
only the key(s) you wanted were added.

[root@proxy-nfs ~]#

[root@proxy-nfs ~]#
ssh-copy-id -i web02

The authenticity of
host 'web02 (192.168.152.136)' can't be established.

ECDSA key
fingerprint is 4c:ee:a3:f1:5c:37:43:32:bd:06:4e:cc:3f:5a:0a:04.

Are you sure you want to continue connecting
(yes/no)? yes

/usr/bin/ssh-copy-id: INFO:
attempting to log in with the new key(s), to
filter out any that are already installed

/usr/bin/ssh-copy-id: INFO:
1 key(s) remain to be installed -- if you are prompted now
it is to install the new keys

root@web02's password:

Number of key(s) added: 1

Now try logging into the
machine, with:   "ssh 'web02'"

and check to make sure that
only the key(s) you wanted were added.

[root@proxy-nfs ~]#
ssh-copy-id -i web03

The authenticity of host 'web03
(192.168.152.137)' can't be established.

ECDSA key
fingerprint is 4c:ee:a3:f1:5c:37:43:32:bd:06:4e:cc:3f:5a:0a:04.

Are you sure you want
to continue connecting (yes/no)? yes

/usr/bin/ssh-copy-id: INFO:
attempting to log in with the new key(s), to
filter out any that are already installed

/usr/bin/ssh-copy-id: INFO:
1 key(s) remain to be installed -- if you are prompted now
it is to install the new keys

root@web03's password:

Number of key(s) added: 1

Now try logging into the
machine, with:   "ssh 'web03'"

and check to make sure that
only the key(s) you wanted were added.

# 修改SSH端口

[root@proxy-nfs ~]# ssh
web01

Last login: Tue Mar 21
15:08:30 2017 from proxy-nfs

[root@web01 ~]# sed -i
s'/^#Port 22/Port 8888/g' /etc/ssh/sshd_config

[root@web01 ~]# grep 8888
/etc/ssh/sshd_config

Port 8888

[root@web01 ~]# exit

logout

Connection to web01 closed.

[root@proxy-nfs ~]# ssh
web02

Last login: Tue Mar 21
14:53:19 2017 from 192.168.152.1

[root@web02 ~]# sed -i
s'/^#Port 22/Port 8888/g' /etc/ssh/sshd_config

[root@web02 ~]# grep 8888
/etc/ssh/sshd_config

Port 8888

[root@web02 ~]# exit

logout

Connection to web02 closed.

[root@proxy-nfs ~]# ssh
web03

Last login: Tue Mar 21
14:53:20 2017 from 192.168.152.1

[root@web03 ~]# sed -i
s'/^#Port 22/Port 8888/g' /etc/ssh/sshd_config

[root@web03 ~]# grep 8888
/etc/ssh/sshd_config

Port 8888

[root@web03 ~]# exit

logout

Connection to web03 closed.

[root@proxy-nfs ~]#

# SCP 远程拷贝文件

[root@proxy-nfs ~]# touch
oldgirl.txt

[root@proxy-nfs ~]# scp
oldgirl.txt web01:/tmp

oldgirl.txt                                                                                                                         
100%    0     0.0KB/s  
00:00

[root@proxy-nfs ~]# scp
web01:/etc/passwd .

passwd                                                                                                                              
100% 2375     2.3KB/s   00:00

五：整理bash命令类型，验证寻找一个命令的优先级

# 以ls命令为例

命令分为：

==> alias
　　==> Compound Commands
　　　　==> function 
　　　　　　==> build_in
　　　　　　　　==> hash
　　　　　　　　　　==> $PATH
　　　　　　　　　　　　==> error: command not found

获取一个命令会按照上述优先级取寻找，先找同名的alias命令，再找compound命令。。。