Create good default labels for a repository. Adapted from https://github.com/amatkivskiy/github-labels-creator.

github-labels.sh

#!/bin/bash

label_names=(
	'Status: Changes Requested' 
	'Status: Do Not Merge' 
	'Status: Help Wanted' 
	'Status: In Progress' 
	'Status: Mergeable' 
	'Status: Review Needed' 
	'Type: Bug' 
	'Type: Duplicate' 
	'Type: Enhancement' 
	'Type: Question' 
	'Type: Wontfix'
    'Priority: Critical'
    'Priority: High'
    'Priority: Medium'
    'Priority: Low'
)
label_colors=(
	'fbca04' 
	'd90ba8' 
	'1d76db' 
	'd4c5f9' 
	'128A0C' 
	'5319e7' 
	'ee0701' 
	'cccccc' 
	'84b6eb' 
	'cc317c' 
	'ffffff'
    'b60205'
    'd93f0b'
    'fbca04'
    '0e8a16'
)
default_labels=(
	'bug'
	'duplicate'
	'enhancement'
	'invalid'
	'question'
	'wontfix'
    'documentation'
	'help%20wanted'
	'good%20first%20issue'
)

echo "Usage: github-labels.sh REPO"

if [[  $# -eq 0 ]]; then
	echo "Not enough parameters for the script to work."
	exit
fi

repository=$1

# Delete default labels
for ((i=0;i<${#default_labels[@]};++i)); do
    response=$(curl --write-out %{http_code} \
      --silent \
      --output /dev/null \
	  -X DELETE \
	  "https://api.github.com/repos/$repository/labels/${default_labels[i]}" \
	  -H "authorization: token $GITHUB_TOKEN" )

	if [ "$response" -eq "204" ]
	then
		echo "Label ${default_labels[i]} has been successfuly deleted"
	else
		echo "Failed to delete ${default_labels[i]}. Code $response"
	fi
done 

# Create custom labels
for ((i=0;i<${#label_names[@]};++i)); do
	response=$(curl --write-out %{http_code} \
      --silent \
      --output /dev/null \
	  -X POST \
	  "https://api.github.com/repos/$repository/labels" \
	  -H "authorization: token $GITHUB_TOKEN" \
	  -H "content-type: application/json" \
	  -d "{\"name\": \"${label_names[i]}\",\"color\": \"${label_colors[i]}\"}")

	if [ "$response" -eq "201" ]
	then
		echo "Successfuly created label ${label_names[i]}"
	else
		echo "Failed to create ${label_names[i]}. Code $response"
	fi
done

To use:

curl -s https://gist.githubusercontent.com/epwalsh/3159dfb4ed3d530e6b8b21ff5a58f5c6/raw/66591aab9b365d9437499b797ad095cf8ddf19aa/github-labels.sh | bash -