From 117fb47f992f0ec4bed6ecb9162b563e654ef5d4 Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Thu, 27 Jun 1996 02:34:30 +0000 Subject: [PATCH] Elaborate on how sort -n works. --- doc/textutils.texi | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/doc/textutils.texi b/doc/textutils.texi index 4f2a291a59..cbe6d7bb7e 100644 --- a/doc/textutils.texi +++ b/doc/textutils.texi @@ -1796,6 +1796,22 @@ Sort numerically: the number begins each line; specifically, it consists of optional whitespace, an optional @samp{-} sign, and zero or more digits, optionally followed by a decimal point and zero or more digits. +@code{sort -n} uses what might be considered an unconventional method +to compare strings representing floating point numbers. Rather than +first converting each string to the C @code{double} type and then +comparing those values, sort aligns the decimal points in the two +strings and compares the strings a character at a time. One benefit +of using this approach is its speed. In practice this is much more +efficient than performing the two corresponding string-to-double (or even +string-to-integer) conversions and then comparing doubles. In addition, +there is no corresponding loss of precision. Converting each string to +@code{double} before comparison would limit precision to about 16 digits +on most systems. + +Note that neither a leading @samp{+} nor exponential notation is +recognized. To compare such strings numerically, use the @samp{-g} +option. + @item -r @opindex -r @cindex reverse sorting -- 2.47.2