[tpm] Implementing a 'less' like pager in perl

Shaun Fryer sfryer at sourcery.ca
Mon Mar 1 19:16:23 PST 2010

The hackish way to do it would be to simply call the pager for them...

my $pager = $ENV{PAGER} || 'most' || 'less' || 'more';
if ($argv0_is_help) {
   if ( the_pager_exists_on_their_system($pager) ) {
       system "perl $0 --helpless | $pager";
   } else {
       print help() and exit;
if ($argv0_is_helpless) {
    print help();

Or something like that... You could probably write something up in
curses, but (apart from legitimate security issue) ... why reinvent
the wheel?
Shaun Fryer

On Mon, Mar 1, 2010 at 9:58 PM, James E Keenan <jkeen at verizon.net> wrote:
> On Mar 1, 2010, at 8:49 PM, Digimer wrote:
>> Hi all,
>>  I like to have built-in '--help' messages in some of my programs, but am
>> always at a loss for how to allow the user to page through it. Usually I
>> have a message at the bottom akin to; "Please call './foo --help |less' to
>> make reading this help message easier".
> ...
>>  I know I could use perldoc, but I don't like assuming that my user knows
>> anything about perl.
> If you "usually" tell the user to call './foo -- help | less', then it
> stands to reason your user is familiar with the Unix command-line.
> In which case, instructing them to call 'perldoc ./foo' is not much of a
> stretch.
> Or, you could create 'man' pages for your programs.  They, too,
> automatically include paging.
> If you wrote POD for your programs, you could use 'pod2man' to generate the
> man pages.  (And I have a CPAN distribution, Pod-Multi, that will let you
> generate documentation from POD simultaneously to text, man and HTML
> format.)
> Jim Keenan
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