Parallel SSH commands execution in pure Bash

parallel_ssh

#!/usr/bin/env bash
#
# Example of parallel SSH execution with colorized hostnames.
# Requires a 256 color-compatible terminal.
#

set -u

declare -a SERVERS=(
  my.server.001
  my.server.002
)

COLORS="$(seq 9 2 229)"

ssh_logger() {
  local host="$1"
  local line
  local color="$(shuf -en1 $COLORS)"
  while IFS= read -r line; do
    printf "[\e[38;5;${color}m%-44s\e[0m] $line\n" "$host"
  done
}

pids=()
log=$(mktemp -t parallel_ssh.XXXXXXXXXX)
trap "rm -f $log" EXIT

for server in ${SERVERS[@]}; do
  echo "==> Spawning SSH for $server <=="
  ssh -A "$server" \
      bash -c 'exec source ~/.bash_aliases; ls -l;' \
    2>&1 | ssh_logger "$server" &>> $log &
  pids+=($!)
done

echo
echo "Waiting ${pids[@]}..."
wait ${pids[@]}

echo
echo "==> LOG <=="
cat $log

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