gistfile1.sh

#!/bin/bash

exec_target() {
    TARGET=$1
    shift
    if ping -c 1 -W 1 $TARGET > /dev/null; then
        "$@" "$TARGET"
    else
        echo "$TARGET unreachable"
    fi
}

RANGE=$(seq 0 25)

PIDS=""

for SEQ in $RANGE; do
    TARGET="10.12.${SEQ}.254"
    exec_target "${TARGET}" "$@" &
    PIDS="$PIDS $!"
done

# wait for all sub processes
for PID in $PIDS; do
    wait $PID
done