Re: bash, sed, SIGPIPE

[Bruno Haible]

Hi Jim,

> Also, even if I do reset the shell's sigpipe handler,
> it doesn't change the fact that sed complains:
> 
>     $ (trap - SIGPIPE; seq 1000000|sed s/1/2/|cmp -s - /dev/null )
>     sed: couldn't write 4 items to stdout: Broken pipe
>     [Exit 1]

Now this looks like a bug either in 'sed' or in your shell. I don't reproduce it
with bash 3.2.39 and sed 4.1.5.

After 'trap - SIGPIPE', sed should get a fatal SIGPIPE signal in these 
conditions.
Quoting 
<http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap>

  "If action is '-' , the shell shall reset each condition to the default 
value."

Whereas the bash manual page says:

  "If arg is absent (and  there  is  a
   single  sigspec)  or  -,  each  specified signal is reset to its
   original disposition (the value it  had  upon  entrance  to  the
   shell)."

Does this last parenthesized sentence mean that the 'trap' command from
build-aux/bootstrap line 263 has an effect on the 'trap' commands in all its
subshells??

Bruno