tool/get_chrome_canary.sh

#!/bin/bash
#
# Ensures the latest Chrome Canary is available, downloading it
# if necessary.
#
# Directory ~/.chrome/canary can safely be cached as the existing
# version will be checked before reusing a previously downloaded
# canary.
#

set -eu

readonly CHROME_URL=https://storage.googleapis.com/chromium-browser-snapshots/Linux_x64
readonly CHROME_REV=$(curl -s ${CHROME_URL}/LAST_CHANGE)

readonly CHROME_CANARY_DIR=$HOME/.chrome/canary
readonly CHROME_CANARY_BIN=$CHROME_CANARY_DIR/chrome-linux/chrome
readonly CHROME_CANARY_REV_FILE=$CHROME_CANARY_DIR/VERSION

function getCanary() {
  local existing_version=""
  if [[ -f $CHROME_CANARY_REV_FILE && -x $CHROME_CANARY_BIN ]]; then
    existing_version=`cat $CHROME_CANARY_REV_FILE`
    echo "Found cached Chrome Canary version: $existing_version"
  fi

  if [[ "$existing_version" != "$CHROME_REV" ]]; then
    echo "Downloading Chrome Canary version: $CHROME_REV"
    rm -fR $CHROME_CANARY_DIR
    mkdir -p $CHROME_CANARY_DIR

    local file=chrome-linux.zip
    curl ${CHROME_URL}/${CHROME_REV}/$file -o $file
    unzip $file -d $CHROME_CANARY_DIR
    rm $file
    echo $CHROME_REV > $CHROME_CANARY_REV_FILE
  fi
}

getCanary >&2

echo $CHROME_CANARY_BIN