Perl与shell的性能比较
分别用shell和perl逐行读一个450M的文本文件，并写入另一文件。
#!/bin/sh
while read line
do
echo $line >> a;
done < "file4read.txt"
while read line
do
echo $line >> a;
done < "file4read.txt"
#!/usr/bin/perl
open ( readfile , "file4read.txt") or die ("Could not open the filen");
open ( writefile , ">b" );
while( $line = <readfile> )
{
print writefile $line;
}
close( writefile );
close( readfile );
open ( readfile , "file4read.txt") or die ("Could not open the filen");
open ( writefile , ">b" );
while( $line = <readfile> )
{
print writefile $line;
}
close( writefile );
close( readfile );
测试结果：
[root@test]# time ./read.sh
real 13m18.797s
user 9m22.840s
sys 3m30.290s
[root@test]#
[root@test]# time ./read.pl
real 0m55.948s
user 0m10.720s
sys 0m2.980s
[root@test]#
相当明显！
kilnt
shell 的读文件循环方式不同，效率差别很大。