判断一个字符串形如compute[164]并能取出compute, 1, 64三个关键值的一段脚本

本代码能处理形如：compute[1-64], compute[01-11], compute[11-99], compute[010-021], compute[1-021], cu[01-64]-ib等多种情况，能满足基本上99%的这种循环输入字符串。 

#!/bin/bash
declare -i iFrom
declare -i iEnd
declare -i iFromLength
declare -i iEndLength
declare -i i

iFromLength=-1
iEndLength=-1
tmpstring="compute[10-64]-ib"

# validate the string syntax
echo $tmpstring | grep -E "[0-9a-zA-Z_-]+\[[0-9]+-[0-9]+\][0-9a-zA-Z_-]*"
if [ $? -ne 0 ]; then
  echo "illegal string..."
  exit
else 
  echo "correct..."
fi

# split the string to get what we want
mainpart_pre=${tmpstring%%\[*\]*}
mainpart_suf=${tmpstring##*\[*\]}
fromindex_tmp=${tmpstring##*\[}
fromindex=${fromindex_tmp%%-*\]*}
endindex_tmp=${tmpstring#*\[*-}
endindex=${endindex_tmp%%\]*}


echo "mainpartpre is $mainpart_pre"
echo "mainpartsuf is $mainpart_suf"
echo "fromindex is $fromindex"
echo "endindex is $endindex"

# if fromindex begins with zero, then fromindex and endindex must have same length
if echo $fromindex | grep -q "^0"; then
    iFromLength=${#fromindex}
    iEndLength=${#endindex}
    if [ $iFromLength -ne $iEndLength ]; then
      echo "$fromindex and $endindex should have the same length, exiting..."
      exit
    fi
    # prefixzero to indicate that we should add "0" to our hostnames
    prefixzero="y"
fi

# get rid of the prefix zeros
fromindex=$(echo "$fromindex" | grep -o "[^0][0-9]*")
endindex=$(echo "$endindex" | grep -o "[^0][0-9]*")

iFrom=fromindex
iEnd=endindex
if [ $iFrom -ge $iEnd ]; then
  echo "illegal iFrom and iEnd..."
  exit
fi

for (( ; iFrom<=iEnd; iFrom++ ))
do
  if [ "$prefixzero" == "y" ]; then
    # fromindex begins with 0
    echo -n ${mainpart_pre}
    for (( i=0; i<(iEndLength-${#iFrom}); i++ )) 
    do
      echo -n "0"
    done
    echo -n $iFrom
    echo $mainpart_suf
  else
    # fromindex doesn't begin with 0, we can generate the hostname directly
    echo ${mainpart_pre}${iFrom}${mainpart_suf}
  fi  
done