VictorVonVolume

_instructions_

This assumes your distro already has inotifywait.

Download jq from here (https://stedolan.github.io/jq/), put the binary in the same folder as vvv.sh.
Update paths in autorun to point to your comics folder, and location of vvv.sh
Be sure to chmod +x both files
Use method of choice to run autorun on startup

Since this only catches volume "1", Mylar needs to be set to never set volume to null.
In Settings > Quality & Post Processing, choose Show Advanced. Check Always set a Volume label.
If this setting isn't visible to you, uncheck Use Start Year as Volume and it should become visible. Change it and then re-check Use Start Year.
Alternatively, set setdefaultvolume to True in your config.ini

This also catches any "null" booktypes, as that makes Komga throw a fit and not load any metadata.

The last line in vvv.sh replaces "comicid" with "cid" to work around Komga not properly identifiying series.json changes otherwise.

To regenerate all series.json files, use this Mylar API call:
http://[path to mylar]/api?cmd=refreshSeriesjson&comicid=all&apikey=[mylar api key]

autorun

pattern="series.json"

inotifywait -q -m -r -e close_write --format %w%f /path/to/comics | while read FILENAME; do
if [[ "$FILENAME" == *${pattern}* ]]; then
  /path/to/vvv.sh "$FILENAME";
fi
done&

vvv.sh

#!/bin/bash
jsonBody=`cat "$1"`

# If series.json already has a "cid" key, it's already been updated with vvv
cidCheck=`jq '.metadata | has("cid")' <<< $jsonBody`
if [ $cidCheck == "true" ]; then
    exit 1
fi

# If volume = 1, set volume to 0
volumeNum=`jq .metadata.volume <<< $jsonBody`
if ([ $volumeNum == "1" ]); then
    jsonBody=`jq '.metadata.volume = 0' <<< $jsonBody`
fi

# If booktype is null, set booktype to "Print"
bookType=`jq .metadata.booktype <<< $jsonBody`
if ([ $bookType == null ]); then
    jsonBody=`jq '.metadata.booktype = "Print"' <<< $jsonBody`
fi

# Change "comicid" to "cid" and write to file
jq --indent 4 '.metadata |= with_entries(if .key == "comicid" then .key = "cid" else . end)' <<< $jsonBody > "$1"