I was approached by a recruiter. There was a phone interview with a general discussion (introduction, goals, "why", etc.) of about 20-30 minutes, followed by a short list of entry-level technical questions (how many addresses are in a /27 network, what command you use for updating initrd, which file you modify for service X, etc.).

After that, there was a second phone interview which lasted 40-45 minutes and was focused on coding (questions below).

They're not hard but require focus and a combination of different skills.

Extract and modify emails and URLs from HTML files.

Find a fast way to extract patterns from a 2D matrix.