System

Grub

Boot System

• 自动挂载项 /etc/fstab etc/rc.local
• 自定义脚本-新建目录(加入环境变量)
• 自定义别名 ~/.bashrc

Configuration

• /etc/default/grub配置文件, 用于一些基本的修改项, 如默认启动项, Grub 界面等待时长, Grub 主题 etc. More details in info -f grub -n 'Simple configuration'

# Default Startup OS
GRUB_DEFAULT=0

# Default Timeout
GRUB_TIMEOUT=5

# https://github.com/vinceliuice/grub2-themes
GRUB_THEME="/boot/grub/themes/Tela/theme.txt"

• /etc/grub.d/*生成/boot/grub/grub.cfg的执行脚本(update-grub命令), 可以更细致地修改启动项, 如各个启动项的名称、顺序等.

Windows Repair

• easyBCD for non-efi loader
• with efi loader, run command:

# root commander
bcdedit /set "{bootmgr}" path \EFI\ubuntu\grubx64.efi

Ubuntu Live Repair

sudo add-apt add-apt-repository ppa:yannubuntu/boot-repair
sudo apt update
sudo apt install boot-repair
boot-repair

SSH

Key

ssh-keygen -t rsa
ssh-add ~/.ssh/id_rsa

SSHD

• config file in /etc/ssh/sshd_config

sudo systemctl reload sshd
sudo service restart sshd

AllowUsers root
AllowUsers sabertaz

Config File

~/.ssh/config:

• Host 别名
  • HostName 主机名(ip) ssh user@ip
  • Port 可忽略
  • User 登录用户名 ssh user@ip
  • PreferredAuthentications publicKey
  • IdentityFile 密钥文件完整路径 ssh -i file

Host github.com
  HostName github.com
  PreferredAuthentications publicKey
  IdentityFile ~/.ssh/id_rsa
Host cs.github.com
  HostName github.com
  PreferredAuthentications publicKey
  IdentityFile ~/.ssh/cs
Host cloud
    HostName xx.org
    User  root
    IdentityFile ~/.ssh/dsl_private_key
Host bwg
    HostName 23.106.150.152
    User root
    Port 29692

git clone git@github.com:user/repo
git clone git@cs.github.com:user/repo

ssh -qTfnN -D 1080 bwg
google-chrome socks5 127.0.0.1 1080

Key File

Setup SSH key:

# Generate SSH key
ssh-keygen -t ed25519 -a 200 -C "your_email@example.com"

# Add SSH public key to remote host
cat ~/.ssh/id_ed25519.pub | ssh b@B 'cat >> ~/.ssh/authorized_keys'

# Add SSH public key to remote host
ssh-copy-id -i ~/.ssh/id_ed25519.pub user@192.168.x.xxx

# Copy SSH private key to clipboard
xclip < ~/.ssh/id_ed25519

# Login to remote host
ssh -i sabertaz root@119.29.140.60

# File transfer
sftp -i sabertaz root@119.29.140.60

# Login to database
mysql -h 10.66.135.125 -P 3306 -u root -p

远程传输文件

rsync -ax -e 'ssh -c blowfish' /root/start_dir root@x.x.x.x:/root/dest_dir

sshpass -p "$DEPLOY_PASSWORD" \
  scp -o StrictHostKeyChecking=no \
      -P $DEPLOY_PORT \
      -r ./build $DEPLOY_USER@$DEPLOY_ADDR:/var/www/html

Systemctl

systemctl enable local

in /etc/init.d/local

#!/bin/bash
### BEGIN INIT INFO
# Provides:          local
# Required-Start:    $all
# Required-Stop:
# Default-Start:     3 4 5
# Default-Stop:
# Short-Description: Personal start script

sslocal -c shadowsocks.json -d start

内存控制

sysctl vm [-options] CONFIG
swapoff

Custom Service

sudo vim /etc/systemd/system/ruoyi-server.service
sudo systemctl daemon-reload
sudo systemctl start ruoyi-server
sudo systemctl enable ruoyi-server
sudo systemctl status ruoyi-server
sudo journalctl -u ruoyi-server -e -f

[Unit]
Description=RuoYi Server Service
After=network.target

[Service]
ExecStart=/usr/bin/java -jar /root/ruoyi-admin.jar
WorkingDirectory=/root
User=root
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=multi-user.target

Crontab

• /etc/crontab
• Crontab Quick Tutorial
• Crontab Generator

crontab -l(list)
crontab -e(establish)

• m,n: 分隔多个时间.
• m-n: 表示时间范围.
• /n: 表示每隔 n 时间.
• 天数与星期之间为逻辑或关系.
• /var/spool/cron/user_name/.
• /var/log/con.
• /etc/cron.*ly: 时间表.
• /etc/anacrontab: 异步时间表.

Job

Background

• jobs —— 所有作业
• atq —— 延时作业队列
• at -M(不使用邮件发送运行结果) -f filename deltaTime
• atrm 作业号/名
• bg/fg 作业号/名
• nohup 脚本 & —— 脱离控制台并后台运行脚本 19 ~ -20 （-20 优先级最高）
• nice -n number 作业号/名
• renice number -p PID

Startup

• /etc/rc.local —— 系统开机任务
• /etc/profile/ /etc/bash.bashrc —— bash 启动任务/远程登陆任务
• /etc/bash.bashrc —— SSH 连接任务

Parallel Execution

命令间插入符

• command1;command2 顺序执行，相当于 C 语言中语句结束符
• command1&&command2 命令同时执行(当 1 正确时)或同时不执行(当 1 出错时)
• command1 || command2 只执行一个命令(正确命令)
• command1 | command2 前一正确命令的输出结果作为后一命令的输入结果

e.g. ls && echo yes >> .log || echo no >> .log