怎么用perl读取txt文件里的所有数字并保存？

perl -pne "s/\..+//" old.txt >new.txt

或者

perl -pne 's/(.+)\.(.+)/$1/' old.txt >new.txt

或者

perl -lne 'print((split /\./)[0])' old.txt >new.txt

方法很多。

All roads lead to Rome ！

#! usr/bin/perl -w

use strict

use warnings

open (FILE,"./a.txt") or die "can't open file:$!"

open (NEWFILE,"./b.txt") or die "can't open file:$!"

while(my $line = <STDIN>)

{

chomp($line)

my $newline = $line =~ s/4/5/g

print NEWFILE $newline

}

close FILE

close NEWFILE