Re: mtab very long

[michael <linux@networkingnewsletter.org.uk>]

On Wed, 2005-05-25 at 12:40 +0200, Maurits van Rees wrote:
> On Wed, May 25, 2005 at 11:28:04AM +0100, michael wrote:
> > On Wed, 2005-05-25 at 12:00 +0200, Urs Thuermann wrote:
> > >     : > /etc/mtab
> > 
> > what's the ':' do???
> 
> Nothing. At least hardly anything worth mentioning. See this snippet
> from the bash manual:
> 
> #####
> SHELL BUILTIN COMMANDS
>        : [arguments]
>     No effect; the command does nothing beyond expanding arguments and
>     performing any specified redirections.  A zero exit code is returned.
> #####
> 
> That also means it doesn't have any output. This empty output
> is now redirected to /etc/mtab, making that file empty. You can try
> other methods as well, e.g. 'cat /dev/null > /etc/mtab'.
> 
> maurits@mauritsvanrees:~$ echo "Hello World" > temp
> maurits@mauritsvanrees:~$ cat temp
> Hello World
> maurits@mauritsvanrees:~$ : > temp
> maurits@mauritsvanrees:~$ cat temp
> maurits@mauritsvanrees:~$
> 
> Does anyone know any other uses for this ':' command?
> 

yes that's what I thought. wasn't quite sure why one would want to wipe
out /etc/mtab but IIRC correctly the suggestion was then to remount
everything so I guess the suggestion was just a way to reconstruct mtab
but why that should help, or rather why the OP's mtab was in a 'mess' I
didn't pick up....

cheers, Michael