[TAG] Talkback:133/cherian.html

[Ben Okopnik]

[Gerry, please remember to include the list in the CC.]

On Fri, Jun 05, 2009 at 11:03:44PM -0500, Papciak, Gerard (Gerry) wrote:
> OK...you indicated sed -i 's/\<whs\>/&2/g' *  
> 
> 1st source of confusion:  \<whs\    ....I understand the backslashes can
> act as 'delimiters', but why the '<'-sign?
 
They're not delimiters; that would be the forward slashes. '\<word\>' is
a construct used to define a stand-alone word rather than a string:

``
echo 'foobar'|sed 's/\<foo\>/xyz/'		# Still 'foobar'
echo 'foo bar'|sed 's/\<foo\>/xyz/'		# Now, it's 'xyz bar'
''
 
> SIMPLER CASE to HELP ME GET THIS...
> 
> fisw1pd2 /export/home/c3782/TEST> sed -i 's/rr/zz/g' *    
> sed: illegal option -- i

Whoops - you've got an older version of 'sed'.

``
ben at Jotunheim:~$ sed --version
GNU sed version 4.1.5
''

That's why I sent along the two different examples.

 
> I have 5 files in a directory: a.dat, b.dat, c.dat, d.dat, e.dat.
> 
> Each contains:  larry, gerry, diane, marianne, john, wally in separate
> lines.
> 
> I want to make each file look like this:  lazzy, gezzy, diane, marianne,
> john, wally.

I'll quote myself from my previous email:

> for file in *
> do
> 	/usr/bin/sed 's/\<whs\>/&2/g' $file > $file.NEW
> 	/bin/mv $file.NEW $file
> done

It would work the same way for the above case:

```
for file in *
do
	/usr/bin/sed 's/rr/zz/g' $file > $file.NEW
	/bin/mv $file.NEW $file
done
'''

Or, as Faber mentioned, you could use Perl. It's had that '-i' option
for a long time now.

```
perl -i~ -wpe 's/rr/zz/g' *
'''

This will make your desired changes in all the files, saving the
originals with a '~' extension. If you don't want the backups, then just
leave off the '~'.


-- 
* Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *