Re: Piping tail -f to fold: tail -f log.txt | fold

[Pádraig Brady]

Bob Proulx wrote:
> Philip Durbin wrote:
>> To word wrap the output of a growing log file I tried. . .
>> $ tail -f log.txt | fold -s
>> . . . and it works fine on NetBSD and Mac OS X, but on the two Linux 
>> distributions I tried (Red Hat and SUSE) I get no output.
> 
> This topic comes up periodically.  Please see this reference for a
> recent more thorough discussion:
> 
>   http://lists.gnu.org/archive/html/bug-coreutils/2008-11/msg00134.html
> 
> In summary it is all about I/O buffering happening in libc's output
> routines.  If the output is not a tty then data is buffered for
> performance reasons into larger chunks before writing.

Well tail -f flushes stdout so it's not actually the problem in this case.
I think this may be due to the i18n changes applied by your distro.

You can disable this logic using the LC_ALL environment variable.
Can you see if this works around the problem for you:

tail -f log.txt | LC_ALL=C fold -s

cheers,
Pádraig.