[K12OSN] How to change X-terminales networks

[Nils Breunese]

Rob Owens wrote:

> I'm not an expert on the syntax, but I know you can use 'sed' for  
> this.
> It'll find and replace text in any file.  Something like:
>
> sed s/192.168.0.254/192.168.10.1/g myconfigfile.txt >  
> myconfigfile.txt.2
>
> That'll find the first IP address in myconfigfile.txt, and replace it
> with the 2nd IP address in myconfigfile.txt.2 -- you'll then have to
> delete the original config file and replace it with the new one.
>
> You could probably put together a script that does a recursive grep
> (grep will find text in a file) and the run sed on that file.  This is
> probably wrong, but it might go something like this:
>
> #!/bin/bash
>
> # Change these variables to suit your needs
> OLDIP=192.168.0
> NEWIP=192.168.10
> SEARCHDIR=/etc
>
> for FILE in `ls -R $SEARCHDIR`
> do
> 	grep $OLDIP $FILE
> 	if [ $? == 0 ]; then
> 		sed s/$OLDIP/$NEWIP/g $FILE > $FILE.new && mv -f $FILE.new $FILE
> 	fi
> done

Instead of creating a new file using sed and then overwriting the old  
file you can use sed with the in-place (-i) flag. If you specify an  
extension with the -i flag, then a backup of the original file will be  
saved using that extension.

You can also replace strings inline using Perl for instance:

	perl -p -i -e 's/OLD/NEW/g' files

Nils Breunese.