# What does \/ do?

I've seen this in some tex file where a word is set in italics, but its ending is in regular font. Trying it out I don't see it making any difference, so I must be missing something. What does the \/ do?

a mwe:

\documentclass{article}
\begin{document}

so many \textit{test}\/s

so many \textit{test}s

\end{document}

• \textit already inserts the \/. You should compare the output with {\itshape test}s to see the difference. – Ulrike Fischer Mar 3 '15 at 11:29

The primitive command \/ adds the italic correction, that's necessary when two “clashing” fonts are used, separated by a space or not. The clashing may be due from the first font being italic or boldface and the second font being upright (but also in other cases).
High level commands such as \textit and \textbf automatically add the italic correction, so your explicit \/ does nothing.