find -exec in bash script with variable expansion

Question

I'm trying to run a command similar to the one below in a bash script. It should search through all subfolders of $sourcedir and copy all files of a certain type to the root level of $targetdir.

#!/bin/bash

# These are set as arguments to the script, not hard-coded
sourcedir="/path/to/sourcedir"
targetdir="/path/to/targetdir"

find "$sourcedir" -type f -name "*.type" -exec sh -c 'cp "$1" "$2/`basename "$1"`"' "{}" "$targetdir" \;

This seems to be pretty close, except that {} isn't being passed in as $2 to -exec sh -c ...

I would like to do this as close to the "right way" as possible, with tolerance for special characters in filenames (specifically single quote characters).

Edit: I see people suggesting using xargs or argument chaining. I was under the impression that this is only ok for a limited number of arguments. If I have, for example, thousands of .jpg files I'm trying to copy from a number of gallery directories into a giant slideshow directory, will the solutions chaining arguments still work?

Edit 2: My problem was I was missing a _ before my first option to sh in the -exec command. For anyone who is curious about how to make the find command work, add the _ and everything will be fine:

find "$sourcedir" -type f -name "*.type" -exec sh -c 'cp "$1" "$2"' _ "{}" "$targetdir" \;

I have accepted an answer below though because it accomplishes the same task, but is more efficient and elegant.

Answer 1

You want to copy files of a specific type, to a specific directory? This is best done with xargs, and you don't even need that sh. This is a more appropriate way to do it, should also run more efficiently.

find "$sourcedir" -type f -name "*.type" | xargs cp -t targetdir

If you need to handle special file names, then use NULL as your seperator

find "$sourcedir" -type f -name "*.type" -print0 | xargs -0 cp -t "$targetdir"

Answer 2

If you don't believe in the church of xargs:

find "$sourcedir" -type f -name "*.mp3" -exec cp -t "$targetdir" {} +

Explanation:

cp -t a b c d 

copies b, c and d to the target dir a.

-exec cmd {} +

invokes the command on a big bunch of files at once, not one after the other (which is standard, if you use ";" instead of +) . This is why we have to pull the targetdir to the front and mark it explicitly as target.

This works for gnu-find and might not for other implementations of find. Of course it relies on the -t -flag too.

TechZilla is of course in so far right, as sh isn't needed to invoke cp.

If you don't use xargs, which is most of the time needless in combination with find, you're saved from learning the -print0 and -0 flag.

Answer 3

You need to pass {} as an argument to the shell then loop over each arg.

find "$sourcedir" -type f -name "*.type" -exec sh -c 'for f; do cp "$f" "$0"; done' "$targetdir" {} +

Note: The way this works is that the first arg to a shell is the name of the shell, we can exploit this by passing the name as the $targetdir and then use the special parameter $0 inside the shell script to access that targetdir.

Answer 4

read -p "SOURCE: " sourcedir
read -p "TYPE: " type
read -p "TARGET: " targetdir
find -L $sourcedir -iname "*.$type" -exec cp -v {} $targetdir \;