See title; In sh-script.el, line ~1631
> (cond ((save-excursion
> (goto-char (point-min))
> (looking-at "#![ \t]?\\([^ \t\n]*/bin/env[ \t]\\)?\\([^ \t\n]+\\)"))
This appears to duplicate auto-mode-interpreter-regexp in files.el, line ~2593:
> (defvar auto-mode-interpreter-regexp
> (purecopy "#![ \t]?\\([^ \t\n]*\
/bin/env[ \t]\\)?\\([^ \t\n]+\\)")
This duplication makes it difficult to customize auto-mode-interpreter-regexp. A discrepancy will cause the wrong shell type (bash, ksh, csh, ...) to be selected.