This is correct (external echo): $ /bin/echo hello world </dev/null 1>&0 /bin/echo: write error: Bad file descriptor $ /bin/echo goodbye world goodbye world $
This is not (builtin echo): $ echo hello world </dev/null 1>&0 bash: echo: write error: Bad file descriptor $ echo goodbye world hello world goodbye world $ The second echo printed the data that failed to get printed by the first one! I am using the bash preinstalled on Ubuntu Gutsy. I have not checked whether it is fixed in later versions: $ bash --version GNU bash, version 3.2.25(1)-release (i486-pc-linux-gnu) Copyright (C) 2005 Free Software Foundation, Inc. $ Russ Cox
