Script for changing SHA-1 hashsum of a formula to SHA-256

brew-rehash

#!/usr/bin/env bash

# Usage: ./brew-rehash.sh formula-file.rb

if [[ $1 == *".rb" ]]; then
  formula=$1
else
  formula="$1.rb"
fi
echo "Rehashing $1"
url=$(cat $formula | grep -m1 "url ['\"]http" | sed "s/.* ['\"]//" | sed "s/['\"]$//")
wget $url -O- > /tmp/formula
if [ $? -ne 0 ]; then
  echo "Download of $1 failed from URL: $url"
fi
actual_sha1=$(shasum -a1 /tmp/formula | sed "s/ .*$//")
expected_sha1=$(cat $formula | grep -m1 sha1 | sed "s/.* ['\"']//" | sed "s/['\"]$//")
if [ "$actual_sha1" = "$expected_sha1" ]; then
  sha256=$(shasum -a256 /tmp/formula | sed "s/ .*$//")
  sed -i.bak "1,/sha1/s/sha1 [\"'].*[\"']/sha256 \"$sha256\"/" $formula
  rm *.bak
else
  echo "SHA-1 for formula $1 do not match; URL: $url"
fi