example perl script with default args and logging

use strict;

use warnings 'all';

use Archive::Tar;

my $DebugLevel = 3 ; 

print defined($ARGV[0]) ? $DebugLevel = $ARGV[0] : "Using max DebugLevel = $DebugLevel", " \n";

my $minimumAmountOfCommandLineArgs = 1 ; 

sub main 

{

logMsg("$0 SCRIPT START " , 1 );

#Action !!!    call here methods

checkCommandLineArgs();        

logMsg("$0 SCRIPT STOP " , 1 );

} #eof sub main

sub checkCommandLineArgs

{

if ( @ARGV != $minimumAmountOfCommandLineArgs )

{

logErrorMsg ( "Not enougn command line args supplied exit 1" , 1 );

die "usage: $0 1 args \n" ; 

exit 1 ; 

} #eof if

else 

{

foreach (@ARGV) { logMsg ( "$_ " ) ;  }

} #eof else         if ( @ARGV != 4 )

} #eof sub checkCommandLineArgs

#log a message according to the DebugLevel

sub logMsg 

{

my $msg = shift ;

my $importance = shift ; 

my $CurrentPerlScriptName = "$0" ; 

my $niceMonth = GetANiceMonth (); 

my $logFile = "$CurrentPerlScriptName" . '_' . "$niceMonth" .  '.log' ; 

$msg = GetANiceTime () .' --- ' .   $msg . " \n" ; 

if ( $importance == 1 ) 

{

$msg = "\n============================================================ \n" . $msg ; 

$msg = $msg . "============================================================ \n" ;

}

#debug nothing

if ( $DebugLevel == 0 ) {     return ; } 

#just print the message

if ( $DebugLevel == 1 ) 

{

print $msg 

} #eof if ( $DebugLevel == 1 ) 

#print the message in 

if ( $DebugLevel == 2 ) 

{

#READ ALL ROWS OF A FILE TO ALIST 

open (LOG, ">> $logFile") || print "could not open the \$logFile $logFile !!!\n"; 

print LOG $msg  ; 

close LOG;

}

#print the message in 

if ( $DebugLevel == 3 ) 

{

#READ ALL ROWS OF A FILE TO ALIST 

open (LOG, ">> $logFile") || print "could not open the \$logFile $logFile !!!\n"; 

print LOG $msg  ; 

close LOG;

print $msg ; 

} #eof if ( $DebugLevel == 3 ) 

} #eof sub logMsg 

#log a message according to the DebugLevel

sub logErrorMsg 

{

my $errorMsg = shift ; 

my $importance  = shift ; 

my $CurrentPerlScriptName = "$0" ; 

my $niceMonth = GetANiceMonth (); 

my $errorLogFile = "$CurrentPerlScriptName" . "_" .  "$niceMonth" . '.error.log' ; 

$errorMsg = GetANiceTime () .' --- ' .   $errorMsg . " \n" ; 

if ( $importance == 1 ) 

{

$errorMsg = "\n============================================================ \n" . $errorMsg ; 

$errorMsg= $errorMsg. "============================================================ \n" ;

}

#debug nothing

if ( $DebugLevel == 0 ) {     return ; } 

#just print the message

if ( $DebugLevel == 1 )  {         print $errorMsg ;     } 

#print the message in a error log file

if ( $DebugLevel == 2 ) 

{

#READ ALL ROWS OF A FILE TO ALIST 

open (ERRLOG, ">> $errorLogFile") || print "could not open the \$errorLogFile $errorLogFile !!!\n"; 

print ERRLOG $errorMsg ; 

close ERRLOG;

}

#print the message in 

if ( $DebugLevel == 3 ) 

{

#READ ALL ROWS OF A FILE TO ALIST 

open (ERRLOG, ">> $errorLogFile") || print "could not open the \$errorLogFile $errorLogFile !!!\n"; 

print ERRLOG $errorMsg  ; 

close ERRLOG;

print $errorMsg ; 

} #eof if ( $DebugLevel == 3 ) 

} #eof sub logErrorMsg 

#GET A NICE TIME 

sub GetANiceTime {

# Purpose: returns the time in yyyymmdd-format 

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time); 

#---- change 'month'- and 'year'-values to correct format ---- 

$min = "0$min" if ($min < 10); 

$hour = "0$hour" if ($hour < 10);

$mon = $mon + 1;

$mon = "0$mon" if ($mon < 10); 

$year = $year + 1900;

$mday = "0$mday" if ($mday < 10); 

return "$year\.$mon\.$mday" . "-" . "$hour\:$min\:$sec"; 

} #eof sub GetANiceTime

sub GetANiceMonth {

# Purpose: returns the time in yyyymmdd-format 

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time); 

#---- change 'month'- and 'year'-values to correct format ---- 

$mon = $mon + 1;

$mon = "0$mon" if ($mon < 10); 

$year = $year + 1900;

return "$year\.$mon" ; 

} #eof sub GetANiceTime

#Action !!!

main(); 

1 ; 

__END__

#Version

#1.0.20101117_110231 --- Yordan Georgiev --- Initial version , copy from Net + args passing 

#1.1.20101118_093059 --- Yordan Georgiev --- Added (error)logging according to DebugLevel