hikey linaro openssl/bio.h: no such file or directory

solution: install openssl

sudo apt install openssl libssl-dev

Refer to:
1. https://discuss.96boards.org/t/linux-support-issue-on-hikey-960/5143/18

Your system requires SMB2 or higher on Windows 10

Control Panel / Programs / Programs and Features / Turn Windows features on or off

Refer to:
1. https://www.guidingtech.com/solve-system-requires-smb2-error-windows-10/
2. https://www.thewindowsclub.com/system-requires-smb2-higher-error-windows-10

VT-x is not available for VirtualBox in Windows 10

1. rum cmd as administrator
2. cmd: bcdedit /set hypervisorlaunchtype off
3. cmd: dism.exe /Online /Disable-Feature:Microsoft-Hyper-V
4. cmd: Dism /Online /Cleanup-Image /RestoreHealth
5. cmd: sfc /scannow
6. Close cmd
7. run PowerShell as Administrator
8. PowerShell: Disable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All
9. Restart














Refer to:
1. https://ugetfix.com/ask/how-to-disable-hyper-v-in-windows-10/

Passwordless SSH access

1. Check for existing SSH keys

# ls ~/.ssh

2. Generate new SSH keys

# ssh-keygen

3. Check for SSH keys

# ls ~/.ssh

4. Copy your pulic key to server

# ssh-copy-id <username>@<ip-address>

or

# cat ~/.ssh/id_rsa.pub | ssh <username>@<ip-address> 'mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys' 

Refer to:
1. https://www.raspberrypi.org/documentation/remote-access/ssh/passwordless.md
2. https://askubuntu.com/questions/46930/how-can-i-set-up-password-less-ssh-login

exFAT support on CentOS 7

yum install -y http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm

yum install exfat-utils fuse-exfat


Refer to: https://bitsanddragons.wordpress.com/2017/09/25/exfat-support-on-centos-7/

The default password of root for Centos 7.

There is no password. Password-based login as "root" is initially disabled. You need to login to to your default (admin) account using SSH and your key, and then run "sudo passwd root" to set a password on the "root" account. Otherwise you have to reset root password during reboot.

Linux dd command usages

dd 指令教學與實用範例，備份與回復資料的小工具 
Refer to: https://blog.gtwang.org/linux/dd-command-examples/
備份整顆硬碟
將 /dev/sda 所有的資料寫入 /dev/sdb：
sudo dd if=/dev/sda of=/dev/sdb conv=noerror,sync

建立硬碟的備份影像檔
sudo dd if=/dev/hda of=~/hdadisk.img

從備份影像檔回復硬碟資料
sudo dd if=hdadisk.img of=/dev/hdb

備份磁碟分割區
sudo dd if=/dev/hda1 of=~/partition1.img

兩個磁碟分割區對拷：
sudo dd if=/dev/sda1 of=/dev/sdb1 bs=4096 conv=noerror,sync

備份 CD/DVD 光碟
sudo dd if=/dev/cdrom of=tgsservice.iso bs=2048

備份 CD/DVD 光碟, 壓縮資料
sudo dd if=/dev/sda | gzip > sdadisk.img.gz

從壓縮過的影像檔回復資料
sudo gzip -dc sdadisk.img.gz | dd of=/dev/sda

Linux 使用 dd 指令將 ISO 檔製作成 Live USB 隨身碟
Refer to: https://blog.gtwang.org/linux/linux-dd-command-write-iso-to-usb-flash-drive/
umount /media/pi/disk
卸載後再次確認一下卸載的 USB 隨身碟是否正確：
lsblk
用 dd 指令將 Linux 的 ISO 映像檔寫入 USB 隨身碟
sudo dd if=ubuntu-16.10-desktop-amd64.iso of=/dev/sdc bs=1M

How to backup and restore (WSL) Windows Subsystem for Linux?

Backup WSL (Windows Subsystem for Linux)


Example: backup_wsl.sh

#! /bin/bash

cd /
tar vzcpf /mnt/i/tmp/ubuntu_`date +%Y%m%d_%H`.tar.gz \
    --exclude=/proc --exclude=/dev --exclude=/mnt --exclude=/media \
    --exclude=/lost+found  --exclude=/tmp --exclude=/sys  --exclude=/run / \
    > /mnt/i/tmp/ubuntu_`date +%Y%m%d_%H`.log \
    2> /mnt/i/tmp/ubuntu_`date +%Y%m%d_%H`.error

Restore WSL using lxrunoffline

# lxrunoffline run -n <distro name> -w
C:\wsl> lxrunoffline run -n mybackup  -w

Refer to:
1. https://superuser.com/questions/1164818/how-to-backup-wsl-linux-subsystem-for-windows-10-before-system-reset-or-reins

Enable VT-x on Win10 by command line

1. Run cmd  with administrator
2. Run bcdedit /set hypervisorlaunchtype on
3. Reboot

Create git repo

Server:
1. sudo rm -rf xxx_sdk
2. sudo git init --bare xxx_sdk
3. sudo chmod 775 -R xxx_sdk
4. sudo chown root:gitgrp -R xxx_sdk


Client:
1. git clone name@192.168.0.124:/home/repos/git/proj/xxx_sdk xxx_sdk
2. git add file
3. git commit -a
4. git push origin master:master