Problem with zcat uncompressing man pages

[Jamie Paul Griffin]

[ Ulrich Spörlein wrote on Wed 26.Sep'12 at 19:02:58 +0200 ]

> On Tue, 2012-09-25 at 12:58:01 +0100, Jamie Paul Griffin wrote:
> > Hi
> > 
> > When I read 'certain' -- not all -- man pages zcat writes a small error to stderr when opening the man page; however, the man page does actually open. The message i get on the terminal is: 
> > 
> > 	zcat: error writing to output: Broken pipe
> > 	zcat: /usr/local/man/man5/muttrc.5.gz: uncompress failed
> > 
> > When closing the man page, another message is shown on stderr:
> > 
> > 	grotty:<standard input> (<standard input>):54131:fatal error: output error
> > 
> > 
> > Would anyone here know the possible cause and fix for this issue?
> 
> Well, what is /usr/local/man/man5/muttrc.5.gz?
> 
> ls -l /usr/local/man/man5/muttrc.5.gz
> file /usr/local/man/man5/muttrc.5.gz
> zcat /usr/local/man/man5/muttrc.5.gz | head -5
> xxd /usr/local/man/man5/muttrc.5.gz | head
> 
> It looks like you simple have a garbled manpage, and the catpage is
> displayed instead.
> 
> Cheers
> Uli

Thanks for your reply. Unfortunately, this is not the only man page it happens with; a number of pages show the same issue, usually with man pages that have been installed with ports.