Unpack AppImage without root rights and AppImage execution

unpack-appimage.sh

#!/bin/bash

# usage: ./unpack-appimage.sh <appimage_file.AppImage>

APP_IMAGE=$(readlink -f $1)
APP_IMAGE_FILE=$(basename ${APP_IMAGE})
APP_DIR=$(dirname $APP_IMAGE)

APP_IMAGE=$(readlink -f $1)
ELFSIZE=$(readelf -h $APP_IMAGE)
START_OF_SECTION=$(echo $ELFSIZE | grep -oP "(?<=Start of section headers: )[0-9]+")
SECTION_SIZE=$(echo $ELFSIZE | grep -oP "(?<=Size of section headers: )[0-9]+")
SECTION_NO=$(echo $ELFSIZE | grep -oP "(?<=Number of section headers: )[0-9]+")
APPIMG_OFFSET=$(( $START_OF_SECTION + $SECTION_SIZE * $SECTION_NO ))

unsquashfs -offset ${APPIMG_OFFSET} -dest ${APP_DIR}/squashfs-root ${APP_IMAGE}