You can use
sed for that. Does it have to be 154 times or was that a generalisation? If you want to replace every occurrence of the word dog with cat in the file test-data and put the results in a file called test-data.new, you can do this:
Code:
sed -e 's/dog/cat/g' test-data > test-data.new
It then becomes a process of checking the data. For example, the word
Dog won't be changed because of the capital D. Have a look at the man page for sed or google for
sed howto tutorial for more info.