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Full Discussion: Update file record inside read loop
Top Forums Shell Programming and Scripting Update file record inside read loop Post 302742631 by Corona688 on Tuesday 11th of December 2012 11:03:09 AM
Old 12-11-2012
Not really, no. There is no seamless 'insert' operation for a file. To add extra data to the middle of a file, you must rewrite all the data that comes after it. That is why inserting data is so complicated, you never really do so.

The usual solutions for doing it all in one step, ed or sed -i, still use a temp file in many implementations.

So, since your records aren't fixed-width, the answer is no. If they were fixed-width, you could change any record without changing the length of the line, making it more possible, but fixed-width records are a difficult thing to handle in shell!
Last edited by Corona688; 12-11-2012 at 12:09 PM..
 

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LEARN ABOUT DEBIAN

interface-order

INTERFACE-ORDER(5)						    resolvconf							INTERFACE-ORDER(5)

NAME

       interface-order - resolvconf configuration file

DESCRIPTION

       The  file  /etc/resolvconf/interface-order is used to control the order in which resolvconf nameserver information records are processed by
       those resolvconf update scripts that consult this file.	(The name of the file is apt because a resolvconf nameserver information record is
       named after the interface with which it is associated.)

       The  file  contains  a sequence of shell glob patterns, one per line.  The position of a record in the order is the point at which its name
       first matches a pattern.

       Patterns may not contain whitespace, slashes or initial dots or tildes.	Blank lines and lines beginning with a '#' are ignored.

       Resolvconf update scripts in /etc/resolvconf/update.d/ that consult this file include the current default versions of  dnsmasq,	pdnsd  and
       libc.   (Actually  they don't read the file directly; they call the utility program /lib/resolvconf/list-records which lists records in the
       specified order and omits the names of empty records.)

EXAMPLE

       # /etc/resolvconf/interface-order
       # Use nameservers on the loopback interface first.
       lo*
       # Next use records for Ethernet interfaces
       eth*
       # Next use records for Wi-Fi interfaces
       wlan*
       # Next use records for PPP interfaces
       ppp*
       # Last use other interfaces
       *

AUTHOR

       Resolvconf was written by Thomas Hood <jdthood@gmail.com>.

COPYRIGHT

       Copyright (C) 2004, 2011 Thomas Hood
       This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
       LAR PURPOSE.

SEE ALSO

       resolvconf(8)

resolvconf							    18 May 2011 						INTERFACE-ORDER(5)
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