Attempt to roll two useful pssh tools (parallel-ssh and parallel-scp) into reusable scripts with our old friend xargs. Link: http://90kts.com/2010/10/31/parallel-ssh-for-osx/

parallel-scp

#!/bin/bash
usage()
{
cat << EOF
Usage: $0 [OPTIONS] -h hosts.txt local remote

     -h  hosts file (each line "host")
     -r  recusively copy directories (OPTIONAL)
     -l  username
     -p  max number of parallel threads (OPTIONAL)
     -O  SSH options (OPTIONAL)

   Example: parallel-scp -h hosts.txt -l koopmans foo /home/koopmans/bar
EOF
}

HOSTS=
RECURSIVE=
USER=
PARALLEL=10
OPTIONS=
while getopts "h:rl:p#t#O:" OPTION
do
  case $OPTION in
    h)
      HOSTS=$OPTARG
      ;;
    r)
      RECURSIVE=-r
      ;;
    l)
      USER=$OPTARG
      ;;
    p)
      PARALLEL=$OPTARG
      ;;
    O)
      OPTIONS=$OPTARG
      ;;
    ?)
      usage
      exit
      ;;
  esac
done

shift $((OPTIND-1))

LOCAL=$1
REMOTE=$2

if [[ -h $HOSTS ]]
then
     usage
     exit 1
fi
cat $HOSTS | awk '{print $1}' | xargs -P $PARALLEL -I{} scp $RECURSIVE $OPTIONS $LOCAL $USER@'{}':$REMOTE

parallel-ssh

#!/bin/bash
usage()
{
cat << EOF
Usage: $0 [OPTIONS] -h hosts.txt prog [arg0] ...
     -h  hosts file (each line "host")
     -l  username
     -p  max number of parallel threads (OPTIONAL)
     -O  SSH options (OPTIONAL)

   Example: parallel-ssh -h hosts.txt -l koopmans uptime
EOF
}

HOSTS=
USER=
PARALLEL=10
OPTIONS=
while getopts "h:l:p#O:" OPTION
do
  case $OPTION in
    h)
      HOSTS=$OPTARG
      ;;
    l)
      USER=$OPTARG
      ;;
    p)
      PARALLEL=$OPTARG
      ;;
    O)
      OPTIONS=$OPTARG
      ;;
    ?)
      usage
      exit
      ;;
  esac
done

shift $((OPTIND-1))

PROG=$@

if [[ -h $HOSTS ]]
then
     usage
     exit 1
fi
cat $HOSTS | awk '{print $1}' | xargs -P $PARALLEL -I{} ssh $OPTIONS $USER@'{}' $PROG