$ npm install -g wwwdiff
$ wwwdiff https://example.com/a https://examle.com/b > sample.png

$ npx wwwdiff https://example.com/a https://examle.com/b > sample.png

$ wwwdiff -h

  wwwdiff is a simple CLI tool to make a diff image between 2 web pages.

  Usage
    $ wwwdiff https://example.com/a https://example.com/b > diff.png
  Options
    --color, -c <color>       hightlighting color. The default is #ff00ff.
    --delay, -d <millisecond> duration until shot. The default value is 0.
    --output, -o <file path>  Use specified file path as output, not sdtout.
    --width, -w <width>       viewport width.
    --verbose                 shows debug messages.

$ wwwdiff https://example.com/a > example.png

# Wait 10 seconds before taking screenshots.
$ wwwdiff --delay 10000 https://example.com/a https://example.com/b > diff.png

# Specify output file with option, not using stdout.
$ wwwdiff https://example.com/a https://example.com/b --output diff.png

# Use specified width for viewport..
$ wwwdiff --width 680 https://example.com/a https://example.com/b > diff.png
$ wwwdiff --width 2048 https://example.com/a https://example.com/b > diff.png

# show debug infomation.
$ wwwdiff --verbose https://example.com/a https://example.com/b > diff.png