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Re: problem with tail -f that need to add to each line constant string a


From: dan12341234
Subject: Re: problem with tail -f that need to add to each line constant string at the beginning of each line
Date: Tue, 1 Nov 2011 00:42:30 -0700 (PDT)

Hi

what if i want to put this commands on a script 

  ssh -n server1 'tail -f /var/log/syslog | sed --unbuffered
"s/^/$(hostname): /"' >>syslog.tail.out & 
  ssh -n server2 'tail -f /var/log/syslog | sed --unbuffered
"s/^/$(hostname): /"' >>syslog.tail.out & 

can you advise

Thanks a lot
Dan




Bob Proulx wrote:
> 
> dan sas wrote:
>> what about if i want to run both commands simultaneous and send the
>> output to a file how can i do that
> 
> This is getting further off topic for the bug bash mailing list.  It
> really isn't too much about bash but just general help with how things
> work.  A better place to ask these types of questions would be the
> address@hidden mailing list.  If you have more questions in
> the future let's please have the discussion there.
> 
> You could put the commands in the background.  To put commands in the
> background use the '&' character at the end of the command line.  
> 
>        If  a  command  is terminated by the control operator &, the shell
> exe-
>        cutes the command in the background in a subshell.  The shell does 
> not
>        wait  for  the command to finish, and the return status is 0. 
> Commands
>        separated by a ; are executed sequentially; the shell  waits  for 
> each
>        command  to terminate in turn.  The return status is the exit
> status of
>        the last command executed.
> 
> And also redirect the output to a file.
> 
>   ssh -n server1 'tail -f /var/log/syslog | sed --unbuffered
> "s/^/$(hostname): /"' >>syslog.tail.out &
>   ssh -n server2 'tail -f /var/log/syslog | sed --unbuffered
> "s/^/$(hostname): /"' >>syslog.tail.out &
> 
> By this point it looks very much like you are trying to re-invent the
> remote logging feature of a syslogd.  Because I now expect a new
> question about how to start and restart this connection automatically.
> (Am I right? :-)  Instead please investigate using one of the syslog
> programs that does exactly that already.  See for example 'rsyslogd'
> which supports remote logging.
> 
> Good luck!
> Bob
> 
> 
> 

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