[PATCH] docs: document dash bug in <>

[Eric Blake]

* doc/autoconf.texi (File Descriptors): Dash 0.5.5 truncates on
<>; at least this was fixed in dash 0.5.6.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog         |    6 ++++++
 doc/autoconf.texi |   12 ++++++++++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9217438..34b3be4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-10-20  Eric Blake  <address@hidden>
+
+       docs: document dash bug in <>
+       * doc/autoconf.texi (File Descriptors): Dash 0.5.5 truncates on
+       <>; at least this was fixed in dash 0.5.6.
+
 2010-10-12  Ralf Wildenhues  <address@hidden>

        tests: avoid AC_CACHE_CHECK test failure with dash.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index b957083..a735209 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -15060,6 +15060,18 @@ File Descriptors
 bash: echo: write error: Communication error on send
 @end example

address@hidden
+Furthermore, older versions of @command{dash} mistakenly truncated
+regular files when using @samp{<>}:
+
address@hidden
+$ @kbd{echo a > file}
+$ @kbd{bash -c ': 1<>file'; cat file}
+a
+$ @kbd{dash -c ': 1<>file'; cat file}
+$ rm a
address@hidden example
+
 When catering to old systems, don't redirect the same file descriptor
 several times, as you are doomed to failure under Ultrix.

-- 
1.7.2.3