To search the current directory for all files called [filename] (a regexp) that contain the given [pattern] (a regexp) and open them in ]program]:
find . -name "[filename]" -exec grep "[pattern]" -ls {} \; | xargs [program]
For example, this will open all ruby files in gvim if they contain the word "logger".
find . -name "*.rb" -exec grep "logger" -ls {} \; | xargs gvim --remote-tab-silent
How we got there...
Search for files
To search a directory for all files of a given filename:
find [directory] -name "[filename]"
E.g. search the current directory for all files with an .rb extension (ruby files):
find . -name "*.rb"
Find text in a file
To search [filename] for a [pattern]:
grep [pattern] [filename]
E.g. search hello.rb for the words "puts 'hi'":
grep "puts 'hi'" hello.rb
Open multiple files in a program
To pass each line returned by a [command] to a [program]:
[command] | xargs [program]
E.g. To cat each file listed by 'ls -C1':
ls -C1 | xargs cat