Delete all remote branches, except master on your fork | github.

remove_except_master.sh

#!/usr/bin/env bash
set -e 

# The MIT License (MIT)

# Copyright (c) 2018 RaviTezu

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

function usage {
    printf "./remove_except_master.sh -r <remote_name> \n"
    printf "Example: ./remove_except_master.sh -r origin \n"
    exit 1
}

while getopts ":r:" opt; do
  case $opt in
    r) REMOTE_NAME="$OPTARG"
    ;;
    \?) echo "Invalid option -$OPTARG" >&2
    echo 
    usage
    ;;
  esac
done

function go_killing {
    # Check if the remote is set.
    if [ -z "$REMOTE_NAME" ]; then
        usage
    fi

    # Check if you are in a git repository or not. 
    YES_GIT=`git rev-parse --is-inside-work-tree`
    if [ "$YES_GIT" == "true" ]; then
        git branch -r | grep $REMOTE_NAME/ > /dev/null 2>&1
        if [ $? -ne 0 ]; then 
            echo "Grrrr.. No such remote exists. Bye!"
	    exit 1
	else
            for branch in $(git branch -r | grep -v 'master$'| grep -v HEAD| cut -d/ -f2); do
                # "|| true" will make the script not exit if the branch doesn't exist on your fork.
                git push $REMOTE_NAME :$branch || true 
            done 
        fi
    else
        echo "Grrr... This  is _not_ a GIT repository. Bye!"
        exit 1 
    fi
}

echo "...... [ Going for a kill ]"
go_killing