假如有一个从WEB上拷贝下来的文件
01 #!/usr/bin/perl -w
02
03 use Tk;
04
05 $Tk::strictMotif = 1;
06
07 $main = MainWindow->new();
08
09 $button1 = $main->Button(-text => "Exit",
10 -command => \&exit_button,
11 -foreground => "orangered" );
12
13 $button1->pack();
14 $button1->configure(-background => "white" );
15 $button2 = $main->Button(-text => "Push Me",
16 -command => \&change_color,
17 -foreground => "black",
18 -background => "steelblue");
19
20 $button2->pack();
21
22 MainLoop();
23
24 sub exit_button {
25 print "You pushed the button!\n";
26 exit;
27 }
28
29 sub change_color {
30 $button1->configure(-background => "red",
31 -foreground => "white");
32 $button2->configure(-background => "maroon",
33 -foreground => "white",
34 -font => "-*-times-bold-r-normal-20-140-*");
35 }
现在想去掉其中的前导数字和空格，可用以下代码解决(打印在屏幕上)
use strict;
use warnings;
my $file="./s1";
if (! open (FILE,"$file")) {
die "can not open file"
}
while (<FILE>) {
chomp;
if (/^(\d+\s+)(\S+)/) { #如果存在前导数字和空格并且不是空代码行，去掉此句将保留空行
s/^(\d+\s+)//; #替换前导数字和空格
print "$_\n";
}
}
当然可以直接修改文件，将修改的结果直接存回原文件，即修改原文件，可以用open文件操作，如下：
use strict;
use warnings;
my $tmp;
my $file="./s1";
my $buffer="./tmp.txt";
open F,"$file" or die $!;
open T,">>$buffer" or die $!;
$^I=".bak"; #空时，则不备份
while ($_=readline F) {
if (defined $_) {
chomp;
if (/^(\d+\s+)(\S+)/) {
s/^(\d+\s+)//;
$tmp=$tmp . "$_\n";
}
}
}
print $tmp;
print T $tmp;
close T;
close F;
rename ("$buffer","$file") or die ("file in use!");
用sed更简洁
sed -i 's/^[0-9]*[ ]*//' s2.txt
sed '/^[[:space:]]*$/d' s2.txt #删除全部空行
