From 0da8fb7d26df9b9df454652a521dfb117efb02a4 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 19 Jun 2012 08:54:39 -0700 Subject: [PATCH] doc: describe -i vs Unicode case folding * doc/grep.texi (Matching Control): Describe how -i differs from Unicode-style case folding. Problem reported by Johannes Meixner in . --- doc/grep.texi | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/doc/grep.texi b/doc/grep.texi index 0e519dd..7c97ac1 100644 --- a/doc/grep.texi +++ b/doc/grep.texi @@ -194,6 +194,12 @@ The empty file contains zero patterns, and therefore matches nothing. @opindex --ignore-case @cindex case insensitive search Ignore case distinctions in both the pattern and the input files. +Currently this operates by lowercasing both the pattern and the input +when checking for matches, so it differs from Unicode-style case folding. +For example, in German @samp{SS} does not match LATIN SMALL LETTER SHARP S, +and GREEK CAPITAL LETTER SIGMA does not match GREEK SMALL LETTER FINAL SIGMA, +even though these would both match under Unicode-style case folding. + @option{-y} is an obsolete synonym that is provided for compatibility. (@option{-i} is specified by POSIX.) -- 1.7.6.5