Finding Unbalanced Parens in Emacs
Oct 17, 2026 05:46

I live in Emacs, and usually only restart it when absolutely necessary. When I do restart, I occasionally get the dreaded message that there’s something wrong with my init file. I’m then prompted to start with the --debug-init switch, which I rarely find helpful. It’s been my experience that the error is often from having unbalanced parens somewhere, and I’ve always found them by brute force—commenting out half of the file, restarting, commenting out another half, restarting, etc. This is a tedious job with an init file that is thousands of lines long.

Recently, I stumbled on the check-parens function. Run it from the beginning of the buffer, and it will stop at the outermost open paren that contains the error. I don’t know how many hours this would have saved me in the past, but better late than never.