这里为大家举二个小例子，供朋友们学习参考。

对任何的函数记录函数运行的时间。
复制代码 代码如下:
#!/usr/bin/perl
use warnings;
use strict;
no strict "refs";
sub testLogToStd{
print "Test stdout : \n";
open LOG,"> 2.txt";
select LOG;
print "just a test\n";
#recover STDOUT
select STDOUT;
print "just a test2\n";
close LOG;
}
sub testFun{
  print "From testFun\n";
  print STDERR "From TestFun Error\n";
}
sub testFun2{
  my $arg1 = shift;
  my $arg2 = shift;
  print "From testFun2\n";
  print $arg1."\n";
  print $arg2."\n";
}
my $log_root = "log" if(! $3 ||$3 == "");
my $ret = system("mkdir $log_root") if(! -e $log_root);
my $report_log = "$log_root/report.log";
open my $REPORTLOG,">",$report_log or die "cannot not open log file report.log\n";
sub logWrapper{
  my $log_root = shift;
  my $REPORTLOG  = shift;
  my $fun = shift;
  my @parameters = @_;
  *old_stdout = *STDOUT;
  *old_stderr = *STDERR;
  open LOG, ">","$log_root/$fun.log" or die "annot open log file $fun.\n";
  *STDOUT = *LOG;
  *STDERR = *LOG;
  my $start = time;
  my $ret = &$fun(@parameters);
  my $end = time;
  *STDOUT = *old_stdout;
  *STDERR = *old_stderr;
  close LOG;
  my $duration = $end - $start;
  print $REPORTLOG "$fun\n";
  print $REPORTLOG "start:".localtime($start)."\n";
  print $REPORTLOG "end:".localtime($end)."\n";
  print $REPORTLOG "duration:".formatTimeDuration($duration)."\n";
  print $REPORTLOG "result:$ret\n";
  print $REPORTLOG "\n";
  print $REPORTLOG "\n";
}
sub formatTimeDuration($){
  my $t = shift;
  my $hrs = int($t/3600);
  my $mins = int($t%3600/60);
  my $secs = int($t%3600%60);
  return "$hrs:$mins:$secs";
}
&logWrapper($log_root,$REPORTLOG,"testFun");
&logWrapper($log_root,$REPORTLOG,"testFun2","arg1","arg2");
print "thanks\n";

若需要调用外部命令，则需要如下：
复制代码 代码如下:
#!/usr/bin/perl
use strict;
use warnings;
# run external commands
# redirect stdout and stderr
sub run_cmd{
  my $cmd = shift;
  my $pid = open(PH, "$cmd 2>&1 |");
  while (<PH>) {print $_; }
}
open(FH, ">", "perl-test.log");
*old_stdout = *STDOUT;
*old_stderr = *STDERR;
*STDOUT = *FH;
*STDERR = *FH;
my $ret = undef;
$ret = readpipe("cp a b ");
$ret = system("cp a b");
$ret = `cp a b`;
run_cmd("cp a b");
print "AA";
print STDERR "BB";
*STDOUT = *old_stdout;
*STDERR = *old_stderr;