From 39e85b7258340611a77a70e2ad46184f1081bbdf Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 16 Mar 2007 06:30:32 +0100 Subject: [PATCH] Fix manual in response to bug reports by Dan Jacobson. * coreutils.texi (sort invocation): Explain numeric sorts better. Compress self-congratulation into a simple "comparison is exact" notice; the --general-numeric-sort option already explains the tradeoffs. (seq invocation): Add example of -f. --- doc/ChangeLog | 9 +++++++++ doc/coreutils.texi | 33 +++++++++++++++++++-------------- 2 files changed, 28 insertions(+), 14 deletions(-) diff --git a/doc/ChangeLog b/doc/ChangeLog index bdae8a2..c4171b8 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,12 @@ +2007-03-15 Paul Eggert + + Fix manual in response to bug reports by Dan Jacobson. + * coreutils.texi (sort invocation): Explain numeric sorts better. + Compress self-congratulation into a simple "comparison is exact" + notice; the --general-numeric-sort option already explains the + tradeoffs. + (seq invocation): Add example of -f. + 2007-03-12 Jim Meyering * coreutils.texi (cp invocation): Mention that --preserve=timestamps diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 6839524..7a4cc2db 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -3575,26 +3575,16 @@ can change this. @opindex --numeric-sort @cindex numeric sort @vindex LC_NUMERIC -Sort numerically: the number begins each line; specifically, it consists +Sort numerically. The number begins each line and consists of optional blanks, an optional @samp{-} sign, and zero or more digits possibly separated by thousands separators, optionally followed -by a decimal-point character and zero or more digits. A string of -no digits is interpreted as @samp{0}. The @env{LC_NUMERIC} +by a decimal-point character and zero or more digits. An empty +number is treated as @samp{0}. The @env{LC_NUMERIC} locale specifies the decimal-point character and thousands separator. By default a blank is a space or a tab, but the @env{LC_CTYPE} locale can change this. -Numeric sort 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, @command{sort} aligns the decimal-point characters 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. +Comparison is exact; there is no rounding error. Neither a leading @samp{+} nor exponential notation is recognized. To compare such strings numerically, use the @@ -13939,6 +13929,12 @@ Print all numbers using @var{format}. @var{format} must contain exactly one of the @samp{printf}-style floating point conversion specifications @samp{%a}, @samp{%e}, @samp{%f}, @samp{%g}, @samp{%A}, @samp{%E}, @samp{%F}, @samp{%G}. +The @samp{%} may be followed by zero or more flags taken from the set +@samp{-+#0 '}, then an optional width containing one or more digits, +then an optional precision consisting of a @samp{.} followed by zero +or more digits. @var{format} may also contain any number of @samp{%%} +conversion specifications. All conversion specifications have the +same meaning as with @samp{printf}. The default format is derived from @var{first}, @var{step}, and @var{last}. If these all use a fixed point decimal representation, @@ -13961,6 +13957,15 @@ decimal representation. @end table +You can get finer-grained control over output with @option{-f}: + +@example +$ seq -f '(%9.2E)' -9e5 1.1e6 1.3e6 +(-9.00E+05) +( 2.00E+05) +( 1.30E+06) +@end example + If you want hexadecimal integer output, you can use @command{printf} to perform the conversion: -- 2.7.4