Help Shell script to pass variables to rsync

Question

I'm trying to create a simple wrapper shell script for rsync. When I send file names to my script, rsync can never seem to identify the correct location. The file names have spaces in them. I've tried a dozen different variations using quotes, double quotes, backslashed quotes, and using the rsync -s --protect-args flag. I'm finally out of ideas. Here is a simplified version of my script.

#!/bin/bash
# Example usage:
#    pull.sh "file 1" "file 2"

LOCATION="/media/WD100"
all_files=""
for file in "$@"; do
        all_files="$all_files:\"$LOCATION/$file\" "
done
# Pull the given files from homeserver to my current directory.
rsync --progress --inplace --append-verify -ave ssh username@homeserver"$all_files" .

Should I be writing this differently? How do make this script work?

UPDATE:

I changed my script to try to reflect Chazelas's answer, but it still seems not to work. Here is my new code:

#!/bin/bash
# Example usage:
#    pull.sh "file 1" "file 2"

LOCATION="/media/WD100"
all_files=""
for file in "$@"; do
    all_files="$all_files\"$LOCATION/$file\" "
done
rsync --progress --inplace --append-verify -0 --files-from=<(printf '%s\0' "$all_files") -ave ssh username@homeserver: .

Running it gives me the standard "usage" output, with this error at the end.

rsync error: syntax or usage error (code 1) at options.c(1657) [server=3.0.9]
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: error in rsync protocol data stream (code 12) at io.c(605) [Receiver=3.0.9]

Answer 1

Use:

# prepend "$location" to each element of the `"$@"` array:
for file do
  set -- "$@" "$location/$file"
  shift
done

rsync ... -0 --files-from=<(printf '%s\0' "$@") user@host: .

Or:

rsync ... -0 --files-from=<(
  for file do
    printf '%s\0' "$location/$file"
  done) user@host: .

to be on the safe side.

That passes the list of files as a NUL delimited list via a named pipe to rsync.

Answer 2

The problem is that you need to quote the file names, but you can't do all that using strings because it will pass all the file names through to rsync as one long string with quotes inside the string (and not individual file string parameters).

The variable $@ is an array in Bash. You need to convert it into a new array when sending to the rsync.

LOCATION="/media/WD100/"
all_files=()
for file in "$@"; do
    all_files+=(":\"$LOCATION$file\"")
done
rsync --progress --inplace --append-verify -ave ssh username@homeserver"${all_files[@]}" .

Answer 3

Since you are copying all the contents of WD100 to the current location, just let rsync sync the contents of the directory.

rsync --progress --inplace --append-verify -ave ssh username@homeserver:/media/WD100/ ./

rsync behaves differently depending on the trailing slash in the path. If there is no slash it copies the directory object recursively, but if there is a slash it will copy the contents of the directory recursively.

Here is the section of the rsync manual that is pertinent.

A trailing slash on the source changes this behavior to avoid creating an additional directory level at the destination. You can think of a trailing / on a source as meaning lqcopy the contents of this directoryrq as opposed to lqcopy the directory by namerq, but in both cases the attributes of the containing directory are transferred to the containing directory on the destination. In other words, each of the following commands copies the files in the same way, including their setting of the attributes of /dest/foo:

rsync -av /src/foo /dest
rsync -av /src/foo/ /dest/foo