copying multiple files to multiple directories

Question

I've a problem copying many files in different directories. Let me explain better:

Let's say I have the following in a dir:

$ ls
file1 file2 file3 file4 file5 dir1 dir2 dir3

and I want to copy every file* in every dir* with a single command. I've tried with:

 echo dir{1..3} | xargs cp file{1..5} '{}' \;

My intent was to tell xargs to process every single dir* from echo and copy all the files in the input processed but this and similar didn't work. I would like to avoid the use of a script because it's a task I have to repeat for about 20 directories and the names of the files are slightly different so I'd prefer modifying a command rather than a script.

Answer 1

echo dir[1-3] | xargs -r -n1 cp file[1-5]

Answer 2

You are making a small mistake in your usage of xargs. Without the -n parameter, xargs append all parameters in input to the command and echo dir{1..3} will not add the necessary carriage return between each entry, so xargs will consider the result as one parameter.

xargs has an option -n which can limit the number of entry, and you need to list the directories with either a \n or \0 as separator:

find . -mindepth 1 -maxdepth 1 -type d -print0 | xargs -0 -n 1 cp file{1..5}

The find command will look for all directories in the current one and use the \0 as separator (which works better if you have directories with spaces) and xargs uses the \0 as separator and launch the command each time with only 1 parameter.

Answer 3

Something like the following should work if they truly have such names:

#!/bin/bash
shopt -s nullglob
for dir in dir*/; do
    cp file* "$dir"
done

If you want to copy all files to all directories regardless of name:

#!/bin/bash
shopt -s nullglob dotglob
for dir in */; do
    for file in *; do
        [[ -f $file ]] && cp "$file" "$dir"
    done
done

Answer 4

You're almost there. You need to run a separate cp command for each destination directory, because cp only makes one copy of every source file. The primary purpose of xargs is to run one command over multiple arguments, but you can tell it to pass a single item at a time with the -n option. Also {} ; is the syntax of find … -exec; you don't need (and can't use) it with xargs.

echo dir{1..3} | xargs -n 1 cp file{1..5}

Note that this only works if your directory names do not contain any whitespace or any of the characters \'", because xargs has no way to tell that those characters are part of file names and not quoting and separating input files. An alternative method that doesn't have any such problem is to use a shell loop:

for d in dirs{1..3}; do
  cp file{1..5} "$d"
done

All this assumes that you can easily distinguish between files and directories by their names. If you can't, you can match directories by adding a / at the end; for example */ matches all directories in the current directories, foo[0-9]*/ matches all directories whose name begins with foo and a digit, etc. There is no similar way to match only non-directories in most shells, but if you pass directories to cp with no argument to tell it to make a recursive copy, the directories are ignored with an error message.

for d in */; do
  cp * "$d"
done

In zsh, you can use glob qualifiers to match only certain file types.

for d in *(/); do
  cp *(.) $d
done