A very useful trick to check your wordpress core integrity with wp-cli.
wp core verify-checksums
– Verify WordPress files against WordPress.org’s checksums.
# Verify checksums
$ wp core verify-checksums
Success: WordPress install verifies against checksums.
# Verify checksums for given WordPress version
$ wp core verify-checksums –version=4.0
Success: WordPress install verifies against checksums.
# Verify checksums for given locale
$ wp core verify-checksums –locale=en_US
Success: WordPress install verifies against checksums.
# Verify checksums for given locale
$ wp core verify-checksums --locale=ja
Warning: File doesn't verify against checksum: wp-includes/version.php
Warning: File doesn't verify against checksum: readme.html
Warning: File doesn't verify against checksum: wp-config-sample.php
Error: WordPress install doesn't verify against checksums.
GLOBAL PARAMETERS
--path=
--ssh=[
Perform operation against a remote server over SSH.
--http=
Perform operation against a remote WordPress install over HTTP.
--url=
Pretend request came from given URL. In multisite, this argument is how the target site is specified.
--user=
Set the WordPress user.
--skip-plugins[=
Skip loading all or some plugins. Note: mu-plugins are still loaded.
--skip-themes[=
Skip loading all or some themes.
--skip-packages
Skip loading all installed packages.
--require=
--[no-]color
Whether to colorize the output.
--debug[=
Show all PHP errors; add verbosity to WP-CLI bootstrap.
--prompt
Prompt the user to enter values for all command arguments.
--quiet
Suppress informational messages.
Learn more here wp-cli doc