random linux notes

install lineageOS on blueline (pixel 3)

copy of https://lineageosroms.com/blueline/ for posterity

Install LineageOS on blueline

Basic requirements

Important: Please read through the instructions at least once before actually following them, so as to avoid any problems due to any missed steps!

Make sure your computer has adb and fastboot. Setup instructions can be found here.
Enable USB debugging on your device.

Unlocking the bootloader

Note: The steps below only need to be run once per device.

Warning: Unlocking the bootloader will erase all data on your device!
Before proceeding, ensure the data you would like to retain is backed up to your PC and/or your Google account, or equivalent. Please note that OEM backup solutions like Samsung and Motorola backup may not be accessible from LineageOS once installed.

Enable OEM unlock in the Developer options under device Settings, if present.
Connect the device to your PC via USB.
On the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
```
adb reboot bootloader
```
You can also boot into fastboot mode via a key combination:
- With the device powered off, hold Volume Down + Power.
Once the device is in fastboot mode, verify your PC finds it by typing:
```
fastboot devices
```
Tip: If you see no permissions fastboot while on Linux or macOS, try running fastboot as root.
Now type the following command to unlock the bootloader:
```
fastboot flashing unlock
```
If the device doesn’t automatically reboot, reboot it. It should now be unlocked.
Since the device resets completely, you will need to re-enable USB debugging to continue.

Temporarily booting a custom recovery using `fastboot`

Download a custom recovery – you can download Lineage Recovery. Simply download the latest recovery file, named something like lineage-17.1-20201116-recovery-blueline.img.
Connect your device to your PC via USB.
On the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
```
adb reboot bootloader
```
You can also boot into fastboot mode via a key combination:
- With the device powered off, hold Volume Down + Power.
Once the device is in fastboot mode, verify your PC finds it by typing:
```
fastboot devices
```
Tip: If you see no permissions fastboot while on Linux or macOS, try running fastboot as root.

Tip: Some devices have buggy USB support while in bootloader mode, if you see fastboot hanging with no output when using commands such as fastboot getvar .. , fastboot boot ..., fastboot flash ... you may want to try a different USB port (preferably a USB Type-A 2.0 one) or a USB hub.
Temporarily flash a recovery on your device by typing:
```
fastboot flash boot <recovery_filename>.img
```
Note: Newer fastboot releases dropped legacy A/B support, so it might attempt to flash to boot__a / boot__b rather than boot_a / boot_b if you try to flash boot. In this case, you must manually specify which slot to flash to based on what slot fastboot failed to flash to. For example, if fastboot fails to flash to boot__a, you must flash to boot_a.

Tip: The file may not be named identically to what stands in this command, so adjust accordingly.
With the device powered off, hold Volume Down + Power.

Installing LineageOS from recovery

Download the LineageOS installation package that you would like to install or build the package yourself.
- Optionally, download additional application packages such as Google Apps (use the arm64 architecture).
If you are not in recovery, reboot into recovery:
- With the device powered off, hold Volume Down + Power.
Now tap Factory Reset, then Format data / factory reset and continue with the formatting process. This will remove encryption and delete all files stored in the internal storage, as well as format your cache partition (if you have one).
Return to the main menu.
Sideload the LineageOS .zip package:
- On the device, select “Apply Update”, then “Apply from ADB” to begin sideload.
- On the host machine, sideload the package using: adb sideload filename.zip
(Optionally): If you want to install any additional add-ons, click Advanced, then Reboot to Recovery, then when your device reboots, click Apply Update, then Apply from ADB, then adb sideload filename.zip those packages in sequence.

Note: Additional add-ons aren’t signed with LineageOS’s official key, and therefore when they are sideloaded, Lineage Recovery will present a screen that says Signature verification failed, this is expected, please click Continue.

Note: If you want Google Apps on your device, you must follow this step before booting into LineageOS for the first time!
Once you have installed everything successfully, click the back arrow in the top left of the screen, then “Reboot system now”.

Warning: Depending on which recovery you use, you may be prompted to install additional apps and services.
We strongly advise you to opt out of installing these, as they may cause your device to bootloop,
as well as attempt to access or corrupt your data.

Update to a newer build of the same LineageOS version on blueline

Updating your device

Note: LineageOS strongly recommends using our builtin Updater app. Alternative methods are supported, however.

Note: addon.d-v2/backuptool_ab, the systems responsible for backing up addons such as GApps/SU do NOT run in recovery on A/B partition scheme (seamless update) devices. Addons are only backed up if you update via the built-in LineageOS Updater app or the push-update script detailed below.

Using the LineageOS Updater app

Open Settings, navigate to “System”, then “Updater”.
Click the Refresh Icon in the top right corner.
Choose which update you’d like and press “Download”.
When the download completes, click “Install”. Once the update process has finished, the device will display a “Reboot” button, you may need to go into the Updater menu in Settings, “System” to see it. This will reboot you into the updated system.

From your PC via the push_update script (Linux/macOS only)

Make sure your computer has working adb. Setup instructions can be found here.
Enable USB debugging on your device. Additionally, open Settings, then “System”, then “Developer Options”, and then either check “Rooted Debugging” (LineageOS 17.1 or above) or select “Root Access Options”, then “ADB Only”.
Run adb root
Run wget https://raw.githubusercontent.com/LineageOS/android_packages_apps_Updater/lineage-16.0/push-update.sh && chmod +x push-update.sh
Run: ./push-update.sh /path/to/zip
Open Settings, navigate to “System”, then “Updater”. click “Install”. Once the update process has finished, the device will display a “Reboot” button, you may need to go into the Updater menu in Settings, “System” to see it. This will reboot you into the updated system.

backup/install android app from adb

search elsewhere for how to enable developer mode, and how to enable usb debugging.

#then find the fullname of the app

$adb shell 'pm list packages' |grep i foo
package:com.bar.android.foo

#Then find the path to the app

$ adb shell pm path com.bar.android.foo
package:/data/app/com.bar.android.foo-asdfasdfasdfasdfasdfas==/base.apk

# then download the app

$ adb pull /data/app/com.bar.android.foo-asdfasdfasdfasdfasdfas==/base.apk

#then later or on another device restore the app

$ adb install -r base.apk

psql restore from pg_dump file – invalid command \N

when searching for this error ‘invalid command \N’ when trying to restore my database from a backup I made with the following:

$ pg_dump -d foo -t bar > bar.psql

I got lots of suggestions but what I needed was to drop the darn table before restoring it …

$psql
foo=> drop table bar;

$psql < bar.psql

postgres 12 create new cluster on different filesystem/port

pg_createcluster -d /var2/lib/postgresql/12/two -l /var/log/postgresql/postgresql-12-two.log -p 5433 12 two

multiple variable looping bash

If you want to loop through something with more than one variable in bash this is your ticket to ride:

#!/usr/bin/env bash
while read -r x y z; do
echo "$x $y $z"
done <<'_____HERE
a b c
1 2 3
x y z
7 8 9
_____HERE

julia postgres libpq update example

The Julia community seems shy about posting examples of database things…

use LibPQ, Tables

db="db" 
server="localhost" 
usr="psql"
passwd="nope"

conn = LibPQ.Connection("host=$server dbname=$db user=$usr password=$passwd")
sql = """select char from foo""" 

conn2 = LibPQ.Connection("host=$server dbname=$db user=$usr password=$passwd") 
sql2 = prepare(conn2, """update bar set agility = \$1 , bravery = \$2 where char = \$3""" ) 

response = execute(conn, sql) 

for row in rowtable(response)
  ag = agility(row[:char])
  br = bravery(row[:char])
  execute(sql2, (ag, br, row[:char]))
end

Goodbye linksys

So the last time I purchased a new wireless router – I tried to find a wireless router that had a future – something where I could replace the stock firmware once the software updates stopped coming from the manufacture. But by this time linksys had sold its soul and stopped shipping wireless routers with the serial headers – my EA6350v2 was one such of these, prior to attempting to solder on pins or making a clothespin serial doohickey, I purchased a backup EA6350v2 off ebay so I wouldn’t have to repeat the cycle if I botched the job. Fortunately the backup EA6350v2 had the serial port pins so I was able to get ddwrt going with out too much fuss. However a few weeks in the wifi was behaving funky on this backup 6350v2 so I went looking for another router – I was looking for a new/better linksys router but came across this sentence: as of October 2020, WE CANNOT ENDORSE BUYING A EA8500 ANYMORE – as linksys has started making it even harder to get alternate firmware installed. So I picked up a Netgear r6300v2, cracked the case, loaded recent version of ddwrt via serial port and added linksys to my never list.

julia mysql mariadb dbinterface update

https://github.com/JuliaDatabases/DBInterface.jl mariadb — mysql

while doing a query on “conn”, I opended second connection “conn2”, and updated the table while stepping through the results of the first query

conn = DBInterface.connect(MySQL.Connection,"localhost","user","pass",db="foo")
sql = """select char from foo"""
response = DBInterface.execute(conn,sql)
conn2 = DBInterface.connect(MySQL.Connection,"localhost","user","pass",db="foo")
sql2 = DBInterface.prepare(conn2, "UPDATE foo set agility = ?, bravery = ? where character = ?")
for row in response
    ag=agility(char)
    br=bravery(char)
    DBInterface.execute(sql2, (ag, br, char))
end

julia complains without the parens around the arguments on the DBInterace.execute line.

load csv into mysql

LOAD DATA LOCAL INFILE ‘/var/tmp/foo.csv’ INTO TABLE foo FIELDS TERMINATED BY ‘,’ ENCLOSED by ‘”‘ LINES TERMINATED BY ‘\n’;

remove opacity from images in hestia wordpress theme

https://docs.themeisle.com/article/562-how-to-remove-opacity-in-hestia

.hestia-ribbon.section-image:after { background-color: rgba(0, 0, 0, 0) !important; }