【总结】Perl技巧
发布时间:2020-12-16 00:32:16 所属栏目:大数据 来源:网络整理
导读:?1. Perl超时机制? eval { my $tmpCmd="ping 192.168.0.1"; local $SIG{ALRM} = sub { alarm 0; die "TIMEOUT"; }; alarm(10); my $startCmdResult = qx($tmpCmd); alarm(0); }; if ($@ =~ /TIMEOUT/) { print "ping timeout";} ? 2. 忽略SIGCHLD信号,避免产
?1. Perl超时机制?
eval { my $tmpCmd="ping 192.168.0.1"; local $SIG{ALRM} = sub { alarm 0; die "TIMEOUT"; }; alarm(10); my $startCmdResult = qx($tmpCmd); alarm(0); }; if ($@ =~ /TIMEOUT/) { print "ping timeout"; } ? 2. 忽略SIGCHLD信号,避免产生僵尸进程 3.等待 sub show_flower { local $| = 1; my @progress_symbol = ('-','','|','/'); my $n = 0; my $count=8; while($count--) { #print "r$progress_symbol[$n]"; $n = ($n>=3)? 0:$n+1; select(undef,undef,0.1); } #print "r"; local $| = 0; }
5. 类似于unix shell中的“此处文档”语法 #!/usr/bin/perl -w $P = 3.1415926; print <<EOF; the price is $P. Hello World. EOF 6. Perl常量的用法 use constant PI => ( 4* atan2(1,1) ); PI=6; # Cannot modify PI; produces an error. use constant DEBUG => 1; print "Pi equals ",PI,"...n" if DEBUG; (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |