My shell script to download the latest bitcoin core client for Linux

#!/bin/bash APP="bitcoin" BASE_URL="http://bit.ly/2s8OUjB" ARCH="arm-linux-gnueabihf" # Raspberry Pi ASC_FILE="SHA256SUMS.asc" CORE_VER="$(curl -sL $BASE_URL | grep -Eo 'bitcoin\-core\-[0-9.]+[0-9]' | sort -V | tail -n 1)" APP_VER="${CORE_VER/bitcoin-core-/}" FILE="${APP}-${APP_VER}-${ARCH}.tar.gz" UNVERIFIED="${FILE}.unverified" FILE_URL="${BASE_URL}${CORE_VER}/$FILE" SHA256SUMS="${BASE_URL}${CORE_VER}/${ASC_FILE}" PGP_KEY="01EA5486DE18A882D4C2684590C8019E36C2E964" echo "Downloading $SHA256SUMS" curl -sqO $SHA256SUMS GNUPGHOME="$(mktemp -d)" export GNUPGHOME echo "Importing PGP signing key" keys=$(gpg --recv-keys --keyserver ha.pool.sks-keyservers.net "$PGP_KEY") [ "$?" -ne 0 ] && echo "Unable to import key" && rm -rf "$ASC_FILE" "$GNUPGHOME" && exit 1 echo "Verifying signature" sig_check=$(gpg --verify "$ASC_FILE") [ "$?" -ne 0 ] && echo "Signature doesn't match $ASC_FILE" && exit 1 download_file() { echo "Downloading $FILE as $UNVERIFIED" curl -s $FILE_URL -o $UNVERIFIED echo "Checking SHA256 hash of $UNVERIFIED" unverified_sum="$(shasum -a 256 $UNVERIFIED)" file_sum="${unverified_sum/.unverified/}" check_sum=$(grep "$file_sum" "$ASC_FILE") if [ "$?" -eq 0 ]; then echo "$FILE downloaded and verified" mv $UNVERIFIED $FILE else echo "$FILE failed SHA256 checksum. Renaming to $FILE.BAD" mv $FILE $FILE.BAD exit 1 fi } if [ ! -f "$FILE" ]; then download_file else file_sum="$(shasum -a 256 $FILE)" check_sum=$(grep "$file_sum" "$ASC_FILE") if [ "$?" -ne 0 ]; then echo "$FILE corrupted. Downloading a new version" download_file else echo "$FILE is the latest" fi fi rm -rf "$ASC_FILE" "$GNUPGHOME" via /r/Bitcoin http://bit.ly/2ZRJqXj