Depends on the industry. Familiarity with the command line for a Java developer is hardly required. Familiarity with the nix command line for a C# developer is utterly useless. Ditto that for video game developers.
On the other hand, if you're writing for linux, then yes, knowing the *nix command line is going to be incredibly useful. That said, there's a lot to "know" - it is its own programming language after all. How much familiarity do you want them to have, and what tradeoffs are you willing to assume if they have that familiarity?