List sorter

The numeric option exists because text sorting puts 10 before 9. Sorted as strings, comparison is character by character, and 1 comes before 9 — so a list of version numbers or file sizes comes out in an order that looks arbitrary. This is the single most common complaint about sorting anywhere, and the reason spreadsheets ask whether a column is text or a number.

Alphabetical sorting here is case-insensitive and locale-aware, which means Apple and apple sort together rather than all the capitals coming first. A plain byte comparison puts every uppercase letter before every lowercase one — Zebra before apple — because that is the ASCII order, and it is almost never what anyone wants. Locale awareness also puts ä next to a rather than after z, which matters for German and Swedish lists and differs between the two.

Deduplication is offered alongside because sorting is when duplicates become visible. It keeps the first occurrence and compares the whole line exactly, so trailing spaces make two otherwise identical lines differ — worth knowing when a list comes out of a spreadsheet, where trailing spaces are common and invisible.