今天遇到一个perl启动后台进程的问题，就是是在启动命令后面加"&"的进程还是顺序，特做此小实验。
a.pl调度
View Code #!/usr/bin/perl -wuse Data::Dumper;my $cmd1="perl b.pl &";my $cmd2="perl b.pl &";my @result=`$cmd1`;my @result1=`$cmd2`;#system($cmd1);#system($cmd2);print Dumper(@result),"\n";print Dumper(@result1),"\n";
这种方式是确实是顺序执行的，但是用system调试是并行的。
b.pl
View Code #!/usr/bin/perl -wprint $$." begin ".current(),"\n";sleep 20;print $$." end ".current(),"\n"; sub current{ my ($sec,$min,$hour,$mday,$mon,$year) = localtime(); $year += 1900; $mon ++; ($sec,$min,$hour,$mday,$mon,$year) = format_date($sec,$min,$hour,$mday,$mon,$year); return "$year-$mon-$mday $hour:$min:$sec";}sub format_date{ my(@items) = @_; my $pattern = "[-\/ :]+"; foreach my $item (@items) { $item = (length($item)==1) ? "0$item":$item; } return @items;}