Is there a Mac keyboard shortcut to "Select Current Line"?
To select an entire line of editable text, assuming a left justified language...

If the insertion point cursor is at the beginning of the line, press:


Command–Shift–Right Arrow   ⌘⇧➡


If the insertion point cursor is at the end of the line, press:


Command–Shift–Left Arrow    ⌘⇧⬅


If the insertion point cursor is at any other part of the line, press:


Command–Left Arrow, Command–Shift–Right Arrow   ⌘⬅ ⌘⇧➡

Note that in this previous key sequence set, that you can keep the ⌘ key pressed while pressing/releasing ⬅ then press ⇧➡ so as to eliminate pressing/releasing the ⌘ key twice.


See the Document shortcuts section in Mac keyboard shortcuts.