wp i18n make-pot . languages/my-plugin.pot
Theme stylesheet detected.
PHP Fatal error: Uncaught Error: Call to undefined function WP_CLI\I18n\mb_ereg() in phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/IterableCodeExtractor.php:145
Stack trace:
#0 phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/IterableCodeExtractor.php(173): WP_CLI\I18n\PhpCodeExtractor::isExcluded(Object(SplFileInfo), Array)
#1 [internal function]: WP_CLI\I18n\PhpCodeExtractor::WP_CLI\I18n{closure}(Object(SplFileInfo), '/var/www/html/g...', Object(RecursiveDirectoryIterator))
#2 [internal function]: CallbackFilterIterator->accept()
#3 phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/IterableCodeExtractor.php(191): FilterIterator->rewind()
#4 phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/IterableCodeExtractor.php(83): WP_CLI\I18n\PhpCodeExtractor::getFilesFromDirectory('/var/www/html/g...', Array, Array, Array)
#5 phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/MakePotCommand.php(529): WP_CLI\I18n\PhpCodeExtractor::fromDirectory('/var/www/html/g...', Object(Gettext\Translations), Arra in phar:///usr/local/bin/wp/vendor/wp-cli/i18n-command/src/IterableCodeExtractor.php on line 145