How do I concatenate files in a subdirectory with Unix find execute and cat into a single file?

Question

I can do this:

$ find .
.
./b
./b/foo
./c
./c/foo

And this:

$ find . -type f -exec cat {} \;
This is in b.
This is in c.

But not this:

$ find . -type f -exec cat > out.txt {} \;

Why not?

Answer 1

find's -exec argument runs the command you specify once for each file it finds. Try:

$ find . -type f -exec cat {} \; > out.txt

or:

$ find . -type f | xargs cat > out.txt

xargs converts its standard input into command-line arguments for the command you specify. If you're worried about embedded spaces in filenames, try:

$ find . -type f -print0 | xargs -0 cat > out.txt