Skip to content

tips.md

Latest commit

 

History

History
603 lines (403 loc) · 10.6 KB

tips.md

File metadata and controls

603 lines (403 loc) · 10.6 KB

Tips

1. For macOS

A. Useful Scripts

a. Hack things

Have a look at this script: bin/macos/hack.sh.

$ bin/macos/hack.sh

b. How to remove unused Xcode simulators

For removing unused iOS simulators from Xcode:

$ xcrun simctl delete unavailable

c. Forward video/audio from Android devices

Firstly, enable USB debugging in the developer menu in the Android device.

Install scrcpy with:

$ brew install scrcpy
$ brew brew install android-platform-tools
(i) How to connect

Here is the guide.

Connect the Android device to macOS with USB cable, and get its IP address with:

$ adb shell ip route

enable adb over TCP/IP with:

$ adb tcpip 5555

disconnect the USB cable, and connect it over TCP/IP with:

$ adb connect YOUR_DEVICE_IP:5555
(ii) Run scrcpy
$ scrcpy --tcpip=YOUR_DEVICE_IP:5555

For forwarding audio only:

$ scrcpy --tcpip=YOUR_DEVICE_IP:5555 --no-video --audio-buffer=400 --audio-bit-rate=320K --turn-screen-off

2. For Raspberry Pi

A. Useful Configurations

a. Setting up watchdog

$ sudo modprobe bcm2708_wdog
$ sudo vi /etc/modules

then add following line:

bcm2708_wdog

Install watchdog and edit conf:

$ sudo apt-get install watchdog
$ sudo vi /etc/watchdog.conf

uncomment following line:

watchdog-device = /dev/watchdog

and restart the service:

$ sudo systemctl restart watchdog

b. Setting up i2c

$ sudo modprobe i2c_dev
$ sudo vi /etc/modules

uncomment following line:

i2c-dev

edit blacklist:

$ sudo vi /etc/modprobe.d/raspi-blacklist.conf

and comment out following lines if exist:

blacklist spi-bcm2708
blacklist i2c-bcm2708

Then do the following:

$ sudo apt-get install i2c-tools
$ sudo usermod -a -G i2c USERNAME

B. Additional Configurations

a. WiFi Configuration

(i) Add a file on the sdcard and reboot

Create a file named wpa_supplicant.conf with following content:

country=JP
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
  ssid="YOUR-SSID"
  psk=YOUR-PSK

  # Protocol type can be: RSN (for WP2) and WPA (for WPA1)
  proto=RSN

  # Key management type can be: WPA-PSK or WPA-EAP (Pre-Shared or Enterprise)
  key_mgmt=WPA-PSK

  # Pairwise can be CCMP or TKIP (for WPA2 or WPA1)
  pairwise=CCMP

  # Authorization option should be OPEN for both WPA1/WPA2 (in less commonly used are SHARED and LEAP)
  auth_alg=OPEN

  # SSID scan technique (0 for broadcast, 1 for hidden)
  scan_ssid=1

  # Priority
  priority=1
}

Replace YOUR-SSID and YOUR-PSK to yours.

YOUR-PSK can be generated like this:

$ wpa_passphrase [SSID] [PASSWORD]

For example,

$ wpa_passphrase my_ssid 0123456789abc

Now put the file on the root of your Raspberry-Pi-ready sdcard and boot with it.

(ii) Edit conf file

Do the same on file: /etc/wpa_supplicant/wpa_supplicant.conf.

$ sudo vi /etc/wpa_supplicant/wpa_supplicant.conf

After that, turn the WLAN device off and on:

$ sudo ifdown wlan0
$ sudo ifup wlan0

Your WLAN device's name may be different from 'wlan0'.

You can list yours with following command:

$ ls /sys/class/net | grep wl

b. AFP & Zero-conf DNS configuration

(i) Install netatalk and avahi-daemon
$ sudo apt-get install netatalk
$ sudo apt-get install avahi-daemon
(ii) Add an avahi-daemon service

Create a service file:

$ sudo vi /etc/avahi/services/SERVICE_NAME.service

and add following lines:

<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name replace-wildcards="yes">%h</name>
  <service>
    <type>_afpovertcp._tcp</type>
    <port>548</port>
  </service>
  <service>
    <type>_http._tcp</type>
    <port>80</port>
  </service>
  <service>
    <type>_ssh._tcp</type>
    <port>22</port>
  </service>
  <service>
    <type>_device-info._tcp</type>
    <port>0</port>
    <txt-record>model=Xserve</txt-record>
  </service>
</service-group>

c. Increase performance/lifespan of storage

Try mounting frequently-written directories (including /tmp) to tmpfs.

For example, this is a part of my /etc/fstab file:

# tmpfs (https://wiki.archlinux.org/title/tmpfs)
tmpfs    /tmp    tmpfs    defaults,noatime,nosuid,size=1536m    0 0
tmpfs    /var/log    tmpfs    defaults,noatime,nosuid,mode=0755,size=128m    0 0

See this article.

d. Enable TRIM on an external SSD

If the SSD supports TRIM,

(i) Add a udev rule

Create /etc/udev/rules.d/10-trim.rules file with the following line:

ACTION=="add|change", ATTRS{idVendor}=="XXXX", ATTRS{idProduct}=="YYYY", SUBSYSTEM=="scsi_disk", ATTR{provisioning_mode}="unmap"

where XXXX is the vendor id and YYYY is the product id

which can be retrieved from lsusb command:

Bus 002 Device 002: ID XXXX:YYYY My Lovely SSD
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
(ii) Enable a timer

For running fstrim automatically, enable a timer with:

$ sudo systemctl enable fstrim.timer

C. Etc. Tips

a. Set static dns server even when using DHCP

Open conf:

$ sudo vi /etc/dhcp/dhclient.conf

and add following line:

supersede domain-name-servers 8.8.8.8, 8.8.4.4;

b. Using bluetooth

(i) With on-board bluetooth module
1. Install required packages

Install pi-bluetooth:

$ sudo apt-get install pi-bluetooth

and reboot.

2. Use bluetoothctl

After reboot, use bluetoothctl for turning up, scanning, and connecting.

$ sudo bluetoothctl

Type help for commands and options.

(ii) With dongle
1. Make Raspberry Pi discoverable by other bluetooth devices
$ sudo hciconfig hci0 piscan
$ sudo bluetooth-agent 0000

Do as the screen says, and make Raspberry Pi hidden from other bluetooth devices again:

$ sudo hciconfig hci0 noscan
2. Display bluetooth device (for checking proper installation)
$ hcitool dev
3. Scan nearby bluetooth devices
$ hcitool scan
4. Settings

Open conf:

$ sudo vi /etc/default/bluetooth

and add/alter following lines:

# edit
#HID2HCI_ENABLED=0
HID2HCI_ENABLED=1

# add static device information
device 01:23:45:AB:CD:EF {
  name "Bluetooth Device Name";
  auth enable;
  encrypt enable;
}

c. Use logrotate.d

Create a file:

$ sudo vi /etc/logrotate.d/some_file

and add following lines:

  /some_where/*.log {
    compress
    copytruncate
    daily
    delaycompress
    missingok
    rotate 7
    size=5M
  }

d. Mount external hdd/ssd on boot time

Open fstab:

$ sudo vi /etc/fstab

and add following lines:

/dev/some_hdd1  /some/where/to/mount1  ext4  defaults   0 0
/dev/some_hdd2  /some/where/to/mount2  vfat  rw,noatime,uid=7777,gid=7778,user   0 0

uid and gid can be retrieved with command 'id'.

e. Run scripts periodically

$ crontab -e

and add following lines:

# every 5 minutes
*/1 * * * * bash -l /some/script_that_needs_login.sh
# every 1 hour
0 1 * * * bash -l -c /some/ruby_script_under_rvm.rb

f. Block IPs temporarily with iptables

$ sudo iptables -A INPUT -s 999.999.999.999 -j DROP

Z. Trouble Shooting

a. Error message: 'smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped'

Append smsc95xx.turbo_mode=N to /boot/cmdline.txt file, and

add/alter following lines in /etc/sysctl.conf:

#vm.vfs_cache_pressure = 100
vm.vfs_cache_pressure = 300
#vm.min_free_kbytes=8192
vm.min_free_kbytes=32768

b. NVMe SSD freezes occasionally

Try appending nvme_core.default_ps_max_latency_us=0 pcie_aspm=off to /boot/firmware/cmdline.txt file.

c. collect2: fatal error: cannot find ‘ld’

Install binutils-gold:

$ sudo apt install binutils-gold

3. For Linux

A. Make a swap file

$ sudo dd if=/dev/zero of=/swapfile bs=1024 count=1M
$ sudo chmod 0600 /swapfile
$ sudo mkswap /swapfile

and append following line to /etc/fstab:

/swapfile swap swap defaults 0 0

B. Configure locale and timezone

$ sudo apt-get install locales tzdata
$ sudo locale-gen en_US.UTF-8
$ sudo locale-gen ko_KR.UTF-8
$ sudo dpkg-reconfigure tzdata

Z. Trouble Shooting

1. Tailscaled is too verbose; syslog gets too big

Create a systemd override file for tailscaled:

$ sudo mkdir -p /etc/systemd/system/tailscaled.service.d
$ sudo vi /etc/systemd/system/tailscaled.service.d/override.conf

and add following lines:

[Service]
LogLevelMax=notice

then restart tailscaled:

$ sudo systemctl daemon-reload && sudo systemctl restart tailscaled

4. For WSL

A. Install WSL

Install WSL on Windows 11 with this guide.

B. Terminal Emulator for WSL

Windows Terminal is recommended.

1. Change starting directory for WSL

Open Windows Terminal's settings and change 'Starting Directory' to: \\wsl$\LINUX-DISTRO\home\USERNAME

where LINUX-DISTRO is your Linux distro's name (eg. Ubuntu), and USERNAME is your linux username.

C. Package Manager

Use winget: Windows Package Manager.

# eg.
$ winget search tailscale
$ winget install tailscale
$ winget upgrade --all

Z. Trouble Shooting

999. Other Tips

A. Server Configurations

a. UTF-8 configuration for MySQL

Open conf:

$ sudo vi /etc/mysql/my.cnf

and add following lines:

[mysql]
default-character-set = utf8mb4

[client]
default-character-set = utf8mb4

[mysqld]
character-set-client-handshake=FALSE
init_connect="SET collation_connection = utf8mb4_unicode_ci
init_connect="SET NAMES utf8mb4"
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci

[mysqldump]
default-character-set = utf8mb4