一个Shell程序的性能优化

#!/bin/bash

#Author Xsh  date:08-15-2006

echo "Time:$(date)==>Strat to processing........." #显示程序开始运行时间

while read numseg

 do

  tmplow="${tmplow} $(expr substr ${numseg} 1 10 & >/dev/null ) " 

  tmptop="${tmptop} $(expr substr ${numseg} 12 10 & >/dev/null ) "

done < ./numseg.txt #循环读取号段文件下限号段存入变量tmplow，上限号段存入变量tmptop
arr_lownug=(${tmplow}) #将下限号段存入数组arr_lownug

arr_topnug=(${tmptop}) #将上限号段存入数组arr_topnug
#定义函数checknum()，输入参数为需要检查的"计费号码"，输出参数为0或者1

#函数checknum()输出为0 表示"计费号码" 不在号段文件的所有号段范围内

#函数checknum()输出为1 表示"计费号码" 在号段文件的所有号段范围内

#函数checknum()中用二分搜索法进行号码的判断

checknum(){ ＃函数定义开始

thisnum=$1

ckresult=0

lowflag=0

topflag=$((${#arr_lownug[*]} - 1 ))   #标注1

MaxIndex=$((${#arr_topnug[*]} - 1 ))  #标注2

midflag=0

midflag=$((${topflag} / 2 ))       #标注3

if [ "${thisnum}" \< "${arr_lownug[0]}" -o "${thisnum}" \> "${arr_topnug[${MaxIndex}]}" ]

then

return 0

else
while [ "$lowflag" != "$midflag" ]

do

if ["$thisnum"\> "${arr_lownug[${midflag}]}" -o "$thisnum" == \

"${arr_lownug[${midflag}]}"]

then

lowflag=${midflag}

midflag=$(( $((${topflag} + ${lowflag})) / 2 )) #标注4

elif["$thisnum"\<"${arr_lownug[${midflag}]}" -o "$thisnum" == \

"${arr_lownug[${midflag}]}"] 

then    

topflag=${midflag}

midflag=$(($((${topflag} + ${lowflag})) / 2 )) #标注5

else

echo "Error!"   

fi

done 

if ["$thisnum" \< "${arr_topnug[${lowflag}]}" -o "$thisnum" == \

"${arr_topnug[${lowflag}]}"]

then

return 1

else 

return 0 

fi

fi

}＃函数定义结束
while read f

do

org="${f:0:10}"  #标注6

checknum ${org}

returnval=$?

if [ "$returnval" == "1"  ]

then 

echo "${f}" >> ./Match_result.cdr  #将匹配的记录存入结果文件1

else

echo "${f}" >> ./NoMatch_result.cdr #将不匹配的记录存入结果文件2

fi

done < ./rttest.txt 

echo "Time:$(date) ==> Proccess is end! "

exit 0;