sed/awk/perl: How to replace all spaces each with an underscore that occur before a specific string ?

[John W. Krahn]

bolega wrote:
> sed/awk/perl:
> 
> How to replace all spaces each with an underscore that occur before a
> specific string ?
> 
> I really prefer a sed one liner.
> 
> Example
> Input :  This is my book. It is too  thick to read. The author gets
> little royalty but the publisher makes a lot.
> Output: This_is_my_book._It_is_too__thick_to read. The author gets
> little royalty but the publisher makes a lot.
> 
> We replaced all the spaces with underscores before the first occurence
> of the string "to ".

$ perl -le'
$x = "This is my book. It is too  thick to read. The author gets little 
royalty but the publisher makes a lot.";
print $x;
$x =~ /to / && substr( $x, 0, $-[0] ) =~ tr/ /_/;
print $x;
'
This is my book. It is too  thick to read. The author gets little 
royalty but the publisher makes a lot.
This_is_my_book._It_is_too__thick_to read. The author gets little 
royalty but the publisher makes a lot.




John
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