php -d xdebug.profiler_enable=1

So to enable profiling on the command line run your script in PHP like this:

php -d xdebug.profiler_enable=1 /path/to/script.php

You need to have configured xdebug in php.ini, I do it with a file in /etc/php/7.2/cli/conf.d/xdebug.ini that looks like this:

;xdebug.profiler_enable = 0
xdebug.profiler_output_dir = "/tmp/xdebug"
xdebug.profiler_output_name = "cachegrind.out.%p"

Note: you can enable profiling for all scripts with xdebug.profiler_enable = 1