How to pipe mailx Headers to external File. Always getting truncated

if the subject of a mail is a little longer then it is not possible to pipe it to any command or external file without getting truncated. Why? And how do you do it correctly?

Example:

mail -H -f mbox

shows several mails. Everything looks OK.

O 3 user@linux.sit Tue May 31 13:39 22/596 This is a very long long long Subject

But as soon as one tries to do ANYTHING with a pipe it will break

mail -H -f mbox | tee
 O  3 user@linux.sit Tue May 31 13:39   22/596   This is a ver

It will only display 78 characters in a row and nothing more.

The same if I do

mail -H -f mbox >> into_a_file

mail -H -f mbox | grep -----
mail -f mbox | less

And it is not working in xterm, in gnome-terminal etc... No matter if I set开发者_Go百科 the COLUMNS or the TERMWIDTH (outside of mailx or with the -S option...)

Why is that?

From what I can see, mailx is behaving differently in giving output versus redirecting it.

Reading the manual shows that the standard output of message headers is possible with

$ mail -H

This is the equivalent of giving output with a specific format (like printf in C)

$ mail -H -S headline="%>%a%m %20f  %16d %3l/%-5o %i%S"

Looks like this is getting truncated for the %S field when piping the output. To preserve the subject header, change the %S to something like %150S (field width 150).

$ mail -H -S headline="%>%a%m %20f  %16d %3l/%-5o %i%150S"