這里為大家舉二個小例子，供朋友們學習參考。

對任何的函數記錄函數運行的時間。
代碼如下:
#!/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";

若需要調用外部命令，則需要如下：
代碼如下:
#!/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;