How can I recursively search all files for a string?
On most recent systems (GNU/Linux/BSD), you would use grep -r pattern . to search all files from the current directory (.) downward.
You can use find if your grep lacks -r:
find . -type f -exec grep -l "$search" '{}' \;The {} characters will be replaced with the current file name.
This command is slower than it needs to be, because find will call grep with only one file name, resulting in many grep invocations (one per file). Since grep accepts multiple file names on the command line, find can be instrumented to call it with several file names at once:
find . -type f -exec grep -l "$search" '{}' \+The trailing '+' character instructs find to call grep with as many file names as possible, saving processes and resulting in faster execution. This example works for POSIX find, e.g. with Solaris.
GNU find uses a helper program called xargs for the same purpose:
find . -type f -print0 | xargs -0 grep -l "$search"
The -print0 / -0 options ensure that any file name can be processed, even ones containing blanks, TAB characters, or new-lines.
90% of the time, all you need is:
Have grep recurse and print the lines (GNU grep):
grep -r "$search" .
Have grep recurse and print only the names (GNU grep):
grep -r -l "$search" .
The find command can be used to run arbitrary commands on every file in a directory (including sub-directories). Replace grep with the command of your choice. The curly braces {} will be replaced with the current file name in the case above.
(Note that they must be escaped in some shells, but not in ["BASH"].)