Question

Is there a way to do this in one line?

my $b = &fetch();
$b =~ s/find/replace/g;
&job($b)

Answer 1

Sure, with a do {} block:

use strict;
use warnings;

sub fetch { 'please find me' }
sub job   { print @_, "\n"   }

job( do { $_ = fetch(); s/find/replace/g; $_ } );

The reason being that in Perl you cannot do fetch() =~ s/find/replace/;:
Can't modify non-lvalue subroutine call in substitution (s///) at ...

Perl 5.14 will introduce the /r flag (which makes the regex return the string with substitutions rather than the number of substitutions) and will reduce the above to:

job( do { $_ = fetch(); s/find/replace/gr; } );

edited thanks to FM: can shorten the above to:

job( map { s/find/replace/g; $_ } fetch() );

And once Perl 5.14 will be out it can be shortened to:

job( map { s/find/replace/gr } fetch() );