Calling rsync with mapfile

Question

Have the following bash codes to deal with filenames passed randomly with mapfile. I want to call rsync on each file and send to a destination path dpath.

mapfile -d '' fl < <(
  find "$dpath" -maxdepth 1 -type f "${inclnm[@]}" |
  shuf -z -n "$nf"
)

Or with shuf working on arguments directly

mapfile -d '' fl < <( shuf -z -n "$nf" -e "${inclnm[@]}" )

How can I modify the two alternatives to run rsync on each file and send to destination?

Answer 1

As said in comments, you don't need to mapfile an intermediate array. Just stream the null delimited selection of files to rsync like this:

#!/usr/bin/env bash

nf=4
inclnm=( a* b* )
# For testing purpose, destination is local host destfolder inside
# user home directory
destination="$USER@localhost:destfolder"

# Pipe the null delimited shuffled selection of files into rsync 
shuf -z -n "$nf" -e "${inclnm[@]}" |
# rsync reads the null-delimited selection of from files from standard input
rsync -a -0 --files-from=- . "$destination"

If you want to collect the random selection of files and use it with rsync then do:

#!/usr/bin/env bash

nf=4
inclnm=( a* b* )
# For testing purpose, destination is local host destfolder inside
# user home directory
destination="$USER@localhost:destfolder"

# Capture the selection of files into the fl array
mapfile -d '' fl < <( shuf -z -n "$nf" -e "${inclnm[@]}" )

# Pass the fl array elements as sources to the rsync command
rsync -a "${fl[@]}" "$destination"