find.1posix . -name file.txt -exec fgrep.1 -H key {} ;
find files
-H     Cause the file information and file type evaluated for  each  symbolic  link  encountered  on  the
       command  line  to  be  those  of  the file referenced by the link, and not the link itself. If the
       referenced file does not exist, the file information and type shall be for the link  itself.  File
       information for all symbolic links not on the command line shall be that of the link itself.
Commands separated  by  a ; are executed sequentially; the shell waits for each command to terminate in turn.  The
return status is the exit status of the last command executed.
source manpages: find