Regular Expression to replace characters in a word?

Question

I am looking for a regular expression that will replace will replace letters in a whole world. I am working on a script that will replace old english words with modern english words... like

He eateth the cow. become He eats the cow.

I cannot seem to get the expression for this. It needs to match whole words too...

Any help would be greatly appreciated.

Answer 1

In most regex languages "\b" matches a word boundary. (But you didn't say exactly which language you are using, so I can't be 100% sure.)



So "\beat\b" matches "I don't know what to eat." But not "I'm beat."

Answer 2

Sed has several commands, but most people only learn the substitute command: s. The substitute command changes all occurrences of the regular expression into a new value. A simple example is changing "day" in the "old" file to "night" in the "new" file:



sed s/day/night/ new



Or another way (for Unix beginners),



sed s/day/night/ old >new



and for those who want to test this:



echo day | sed s/day/night/

Answer 3

You can use \b to match a word boundary, so "\beateth\b" will match "he eateth the cow" but not "he seateth the dog".