Changing a greek letter control sequence

Question

I have a TeX document with many occurrences of a Greek letter, say \kappa. Is there a command to change all \kappas to another letter, say \omega all at once, without changing each \kappa to \omega manually?

Answer 1

Something as simple as this:

\renewcommand{\kappa}{\omega}

in the preamble?

The only caveat is that it'll no longer be possible to use \kappa for κ, so if you want to map something else to κ, it won't work. If needed, you can use \let to “save” the old \kappa with a different name. E.g., if you wanted to switch \omega and \kappa you could do:

\let\oldkappa=\kappa
\let\oldomega=\omega
\renewcommand{\kappa}{\oldomega}
\renewcommand{\omega}{\oldkappa}

Don't just use renewcommand with both the old names, or you'll at best end up with two commands the same, and at worst with circular definitions and neverending compilation process.