--- a/scripts/plot/semilogy.m
+++ b/scripts/plot/semilogy.m
@@ -17,15 +17,13 @@
 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 ## 02111-1307, USA.
 
-## usage: semilogy (x, y)
-##        semilogy (x1, y1, x2, y2, ...)
-##        semilogy (x, y, fmt)
-##
-## Make a 2D plot of y versus x using a log scale for the x axis.
-##
-## See the help message for the plot command for a description of how
-## the arguments are interpreted.
-##
+## -*- texinfo -*-
+## @deftypefn {Function File} {} semilogy (@var{args})
+## Make a two-dimensional plot using a log scale for the @var{y} axis.  See
+## the description of @code{plot} for a description of the arguments
+## that @code{semilogy} will accept.
+## @end deftypefn
+
 ## See also: plot, semilogx, loglog, polar, mesh, contour, bar, stairs,
 ##           gplot, gsplot, replot, xlabel, ylabel, title