Shell Programming and Scripting

#!/bin/bash
servers=(
 1.1.1.1 2.2.2.2
 3.3.3.3 4.4.4.4
 5.5.5.5
)
# /bin/ksh syntax:
#set -A servers 1.1.1.1 2.2.2.2 3.3.3.3 4.4.4.4 5.5.5.5

sindex=0
smax=${#servers[@]}

for file in *
do
 server=${servers[$sindex]}
 # execute the ( subshell ) in the background
 (
 echo "transfer $file to $server"
 sleep 10
 ) &
 sindex=$(( sindex + 1 ))
 if [ $sindex = $smax ] 
 then
  sindex=0
  wait
 fi
done

#!/bin/bash
servers=(
 1.1.1.1 2.2.2.2
 3.3.3.3 4.4.4.4
 5.5.5.5
)
# /bin/ksh syntax:
#set -A servers 1.1.1.1 2.2.2.2 3.3.3.3 4.4.4.4 5.5.5.5

sindex=0
smax=${#servers[@]}
maxjobs=$smax

for file in *
do
 # ensure it is a file
 [ -f "$file" ] || continue
 server=${servers[$sindex]}
 # execute the ( subshell ) in the background
 (
 echo "transfer $file to $server"
 sleep $(( RANDOM % 10 ))
 ) &
 sindex=$(( (sindex + 1) % smax ))
 # poll the number of jobs until it becomes less than maxjobs
 until [ `jobs | wc -l` -lt $maxjobs ]
 do
  sleep 2
 done
done