Latest Log Errors

A two-step search over a real directory of log files: first find which file to look at, using the filesystem, then find what's wrong in it, using its content.

Input

$1 is the path to a directory. It contains a flat mix of files (some .log, some not), each with a real last-modified time.

Steps

1. Among the .log files directly inside $1 (never look in subdirectories), find the single one that was modified most recently. If two or more .log files are tied for the latest mtime, use whichever sorts first alphabetically.
2. Print every line in that one file containing the literal text ERROR (a plain substring match — a line containing NOT_AN_ERRORCODE counts), in the file's own order.

If there are no .log files at all, or the most recent one has no ERROR lines, print nothing.

Constraints

• At most 10,000 files in the directory.
• At most 10,000 lines in any single file.
• Non-.log files are never candidates in step 1, no matter how recently they were modified.

Example

Directory contents (name — last modified):

payments.9f3e7a21.log      — 10 days ago
auth-service.a1b2c3d4.log  — 1 day ago   (most recently modified .log file)
worker-queue.5c8d0e12.log  — 5 days ago
README.md                  — 1 hour ago  (not a .log file — ignored despite being newest)

auth-service.a1b2c3d4.log's content:

10:00 INFO starting up
10:05 ERROR connection refused
10:10 INFO retrying
10:12 ERROR timeout
10:15 INFO recovered

Output:

10:05 ERROR connection refused
10:12 ERROR timeout