娜然的专栏

[root@mysql1 perl]# cat 1.pl#!/usr/bin/env perlprint "hello world!\n";print "hello world";[root@mysql1 perl]# cat 2.pl#!/usr/bin/env perluse 5.010;say "hello world!";

[root@mysql1 perl]# cat 19.pl #!/usr/bin/env perluse warnings FATAL => 'all';sub max {  my($max_so_far)=shift @_;  foreach (@_) {    if ($_ > $max_so_far) {      $max_so_far=$_;

[root@mysql1 perl]# cat 21.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';sub which_element_is {  foreach(@_) {  print $_,"\n";  }  my($what,@array)=@_;

[root@mysql1 perl]# cat 23.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';use 5.010;sub marine {  my $n += 1;  print "hello, sailor number $n!\n";}sub marin

[root@mysql1 perl]# cat 25.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';sub total {  my $sum;  foreach (@_) {    $sum+=$_;  }  $sum;}print "the number

[root@mysql1 perl]# cat 27.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';use 5.010;sub greet {  state $last_person;  my $name=shift;  print "hi $name! ";

[root@mysql1 perl]# cat test.pl #!/usr/bin/env perlwhile (defined($line=  chomp($line);  print "it was $line that i saw!\n";}[root@mysql1 perl]# ./test.pl a

[root@mysql1 perl]# cat test1.pl   #!/usr/bin/env perluse strict;use warnings;my $user='gw';my $days_to_die=36500;printf "hello, %s; your password expires in %d days!\n", $user,$da

[root@mysql1 perl]# cat 28.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';my @items=qw( wilma dino pebbles );my $format="the items are:\n".("%10s\n" x @items);pri

if ( ! open LOG, '>>', 'logfile' ) {  die "cannot create logfile: $!";}如果open失败，die会终止程序的运行，并且告诉我们无法创建日志文件$!：会给我们一个解释，如：fine not found之类的，也就是在c或其他语言里面调用perror取得的字符串。    这个解释性的系统错误信息保

[root@mysql1 perl]# cat 18.pl   #!/usr/bin/env perl#use warnings FATAL => 'all';sub max {#  my($m,$n);#  ($m,$n)=@_;my($m,$n)=@_;  if ($m > $n) {    $m  } else {    $n  }

[root@mysql1 perl]# cat 15.pl #!/usr/bin/env perl#use warnings FATAL => 'all';sub sum_of_fred_and_barney {  print "hey, you called the sum_of_fred_and_barney subroutine!\n";  $fred +

[root@mysql1 perl]# cat 5.pl #!/usr/bin/env perlprint "enter some lines, then press ctrl-D:\n"; #或者试试ctrl-Z@lines=;@reverse_lines=reverse @lines;print @reverse_lines;[root@mysql1 perl]

[root@mysql1 perl]# cat 8.pl #!/usr/bin/env perlchomp(@lines=);@sorted=sort @lines;print "@sorted\n";[root@mysql1 perl]# [root@mysql1 perl]# [root@mysql1 perl]# ./8.pl caba b

[root@mysql1 perl]# ./9.pl the circumference of a circle of radius 12.5 is 78.53981635.[root@mysql1 perl]# cat 9.pl #!/usr/bin/perl -w$pi=3.141592654;$circ=2 * $pi * 12.5;print "the ci

[root@mysql1 perl]# ./10.pl what is the radius? 0the circumference of a circle of radius 0 is 0.[root@mysql1 perl]# ./10.pl what is the radius? 1the circumference of a circle of radius 1 is

[root@mysql1 perl]# cat 11.pl  #!/usr/bin/perl -w$pi=3.141592654;print "what is the radius? ";chomp($radius=);$circ=2 * $pi * $radius;if($radius$circ=0;}print "the circumference

[root@mysql1 perl]# cat 12.pl #!/usr/bin/env perlprint "enter first number: ";chomp($one=);print "enter second number: ";chomp($two=);$result=$one * $two;print "the result is $result

[root@mysql1 perl]# cat 13.pl #!/usr/bin/env perlprint "enter a string: ";$str=;print "enter a number a times: ";chomp($num=);$result=$str x $num;print "the result is:\n$result";pr

[root@mysql1 perl]# cat 14.pl #!/usr/bin/env perlsub marine {  $n += 1;  # 全局变量$n  print "hello, sailor number $n|\n";}sub marine1 {  my $n += 1;  print "hello, sailor number $

如果在perl中你定义了一个子程序，并且启用了警告，子程序中的运算结果没有被存储起来，这时候perl会将其丢弃，并且报错：Useless use of addition (+) in void context at来警告你，其中的void context（空的上下文），表示运算结果没有存储到变量里，也未被任何函数使用。例子：[root@mysql1 perl]# cat 16.pl #

[root@mysql1 perl]# cat 35.pl #!/usr/bin/env perluse strict;use warnings FATAL => 'all';use 5.010;print "hello!\n";print "hello!","\n";say "hello!";[root@mysql1 perl]# [r