[vox-tech] Using awk or perl to find and replace

[Foo Lim]

On Wed, 24 Nov 2004, Trevor M. Lango wrote:

> On Tuesday 23 November 2004 23:41, Foo Lim wrote:
> > On Tue, 23 Nov 2004, Trevor M. Lango wrote:
> > > I have been reading the man pages and I'm lost.  I want to scan through
> > > an input file for an expression with this pattern:
> > >
> > >     h.*.JPG
> > >
> > > and replace it with an expression with the following pattern:
> > >
> > >     *.h.JPG
> > >
> > > Perl and awk both appear to be ideal candidates for just such a task
> > > but I'm a serious newbie to both of 'em.  Any help much appreciated!
> >
> > Hi Trevor,
> >
> > Does the pattern "h.*.JPG" match something like this: h.abc123.JPG ?
> 
> Something like this: "h.#-##-####-####.###.JPG"
> 
> > Since the period "." is a metacharacter in regular expressions.  If that's
> > the case, then a perl script like this would work:
> >
> > while (<>) {
> >   s/h\.(.*)\.JPG/$1.h.JPG/g;
> >   print;
> > }
> >
> > FL

The code above should work.  If it's possible to have multiple files on a 
line, you may want to change the regex to this:

  s/h\.(.*?)\.JPG/$1.h.JPG/g;

instead, so it will minimal match instead of do a greedy match.

HTH,
FL