Ubuntu18 使用筆記

Ubuntu18 配置全局JDK環境

# 1 配置/etc/profile 配置全局JDK環境變量

# 1.1 使用 vim 編輯 /etc/profile
vim /etc/profile  
# 1.2 使用 Ubuntu18 自帶文本編輯器編輯 /etc/profile
gedit /etc/profile
 
# 1.3 在 /etc/profile 最後添加
#java environment
export JAVA_HOME=/home/ubuntu/software/java/jdk1.8.0_191
export JRE_HOME=${JAVA_HOME}/jre  
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
 
# 2 保存退出
source /etc/profile

# 3 使用命令檢查是否安裝成功
java -version
javac -version

# 4 如果能看到輸出信息，說明按轉配置jdk成功
# 5 如果切換root用戶後 不能使用java或者javac命令
update-alternatives --install /usr/bin/javac javac /home/sinosoft/software/java/jdk1.8.0_191/bin/javac 300
update-alternatives --install /usr/bin/java java /home/sinosoft/software/java/jdk1.8.0_191/bin/java 300
update-alternatives --config java

Ubuntu18 自定義靜態 IP
使用 ipconfig 或者 ip addr 查看 Ubuntu IP地址信息

root@sitserver:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:fe:46:b5 brd ff:ff:ff:ff:ff:ff
    inet 192.168.50.33/24 brd 192.168.50.255 scope global dynamic noprefixroute ens33
       valid_lft 57414sec preferred_lft 57414sec
    inet6 fe80::428f:5bb4:3c8c:a51b/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

編輯 /etc/netplan/01-network-manager-all.yaml
gedit /etc/netplan/01-network-manager-all.yaml 或者 vim /etc/netplan/01-network-manager-all.yaml
/etc/netplan/01-network-manager-all.yaml 對排版要求嚴格

# Let NetworkManager manage all devices on this system
network:
      ethernets:
            ens33:
               addresses: [192.168.50.100/24]
               gateway4: 192.168.0.1
               dhcp4: no
               dhcp6: no
            nameservers:
               addresses: [223.5.5.5/24,223.6.6.6/24,8.8.8.8/24]
      version: 2

應用自定義靜態 IP 地址

netplan apply

配置 DNS vim /etc/systemd/resolved.conf 使虛擬機可以連接網絡

#  This file is part of systemd.
# 
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See resolved.conf(5) for details

[Resolve]
DNS=223.5.5.5
#FallbackDNS=
#Domains=
#LLMNR=no
#MulticastDNS=no
#DNSSEC=no
#Cache=yes
#DNSStubListener=yes