The horrible bug your command line Perl program probably has
It talks about the best practice to test always system call return values. But also make a good point that many user forget about to test the result of get-option. If you don't know what get_option is, and you are writing perl scripts for comand line usage, then you are missing a very important tool.
For the record, I am putting here my standard get_option scaffold (I have it as a template in my .emacs)
use Getopt::Long;
my $prog = $0;
my $usage = <<eoq;
Usage for $0:
>$prog [-test -help -verbose]
EOQ
my $help;
my $test;
my $debug;
my $verbose =1;
my $log;
my $stdout;
my $ok = GetOptions(
'test' => \$test,
'debug:i' => \$debug,
'verbose:i' => \$verbose,
'help' => \$help,
'log' => \$log,
'stdout' => \$stdout,
);
if ($help || !$ok ) {
print $usage;
exit;
}
my $prog = $0;
my $usage = <<eoq;
Usage for $0:
>$prog [-test -help -verbose]
EOQ
my $help;
my $test;
my $debug;
my $verbose =1;
my $log;
my $stdout;
my $ok = GetOptions(
'test' => \$test,
'debug:i' => \$debug,
'verbose:i' => \$verbose,
'help' => \$help,
'log' => \$log,
'stdout' => \$stdout,
);
if ($help || !$ok ) {
print $usage;
exit;
}
I am capturing the return value of the getoptions and printing a 'usage' message if error or help
I encourage you to put this in your editor's perl templates.
Posts
2 comments:
Instead of a usage string, why not add Pod::Usage? Then your usage statement comes right from your man page.
[to oylenshpeegul] Yes Pod::Usage is nice, the thing is that I want to separate the usage string from the pod (rendering the pod takes time). So I can do 'perl myprogram.pl -h' and find quickly the options for the program.
I heard about it but I have never used it. Reading again now the pod for Pod::Usage I see that with verbosity 0 it prints only the synopsis. I will see if this is fast enough.
Thanks
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