for file in `ls **/*.txt`;do perl -pi -w -e ‘s/SEARCH_FOR_THIS/REPLACE_WITH_THIS/g;’ $file; done

The nested ‘perl’ command can work kind of like ‘sed’.  Here are what the arguments being passed in mean:

-e means execute the following line of code.
-i means edit in-place
-w write warnings
-p loop

What I’ve got before me is a target/lib directory full of all of my maven2-managed dependencies.  I need to add each jar file explicitly into the classpath – barf!

Well, here’s a handy little shell script which will build that string for you:

for file in `ls lib`; do echo -n ‘lib/’ >> classpath.txt;echo -n $file >> classpath.txt;echo -n ‘:’ >> classpath.txt;done

Awesome – so just open the classpath.txt file and use that big ‘ol path however you want to.  Windows users would use a semi-colon instead of a colon above.  Also, remember that you need to specify the classpath option prior to the name of the class to run – otherwise the classpath is ignored ( as it is assumed to be an argument to the program and not a jvm option ).