stream data to multiple pipes

multi-fifo

#!/bin/bash
# as introduced here: http://fernandoipar.com/2011/03/10/piping-data-to-multiple-processes/

usage()
{
cat <&2

usage : multi-fifo target0 [target1 [target2 [...]]]

Where each targetN is a program you want to send the input multi-fifo receives

EOF

}

[ $# -eq 0 ] && usage && exit 1

i=0
pipeline="tee /dev/null"
while [ -n "$1" ]; do
target=$1
fifo=/tmp/multi-fifo-$$.$i
mkfifo $fifo
eval "$target < $fifo" &
pipeline="$pipeline | tee $fifo"
i=$((i+1))
shift
done

eval "cat | $pipeline"

j=0
while [ $j -lt $i ]; do
rm -f /tmp/multi-fifo-$$.$j
j=$((j+1))
done