Thursday, 13 September 2007

The Beast Remade: Term::Shell Basics

Grabbing and parsing the web pages are all very well, but without a fast way to interact with them this is all just a waste of time and effort. Term::Shell by Neil Watkiss has been at version 0.01 for half a decade (woo! recently updated to 0.02!), and is barely mentioned in a Google search. That does not deter a Perl-familiar sysadmin out to improve his daily routine. A non-interactive critical script would be another matter entirely.

Term::Shell is excellent scaffolding and support when you do not want to muck around with Term::Readline yourself. As long as you have one of the Term::Readline:: alternatives installed, you get command-line editing and history for free.

A demonstration:

knan@viconia:~$ perl ./
World domination. But first, take care of the spam.
spsh:/> ls
No spam. Yet.
spsh:/> ?
Unknown command '?'; type 'help' for a list.
spsh:/> help
Type 'help command' for more detailed help.
exit - exits the program
help - prints this screen, or help on 'command'
ls - Is there any spam? - no help available
spsh:/> exit

So far so good. Add a help_ls subroutine if you feel like explaining the intricacies of spam listing to your fellow spam handlers.

Source of the shell above:

package main;


package Spsh;
use base qw(Term::Shell);

sub preloop
$state_path = "";
binmode(STDOUT, ":utf8");

print "World domination. But first,"
."take care of the spam.\n";

sub prompt_str
return "spsh:/$state_path> ";

# Define an empty command, to avoid
# "unknown command" on an empty
# command-line.
sub run_

sub run_ls
print "No spam. Yet.\n";

sub smry_ls
return "Is there any spam?"

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