Re: Simulating Command Line History in Perl

I've looked at the Term::Readline::* modules, but none of them seem to do this part of the task.

They do — at least on *nix (preferably install Term::ReadLine::Gnu, which has quite a few more features)

#!/usr/bin/perl

use Term::ReadLine;

my $term = new Term::ReadLine 'Demo';
my $prompt = 'Perl> ';

while ( (my $cmd = $term->readline($prompt)) ne 'quit') {
    print "cmd: '$cmd'\n";
}
[download]

You can supply a second argument to readline() in case you want to suggest some default input (which can be edited).

Comment on Re: Simulating Command Line History in Perl Select or Download Code

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Re^2: Simulating Command Line History in Perl by Anonymous Monk on Apr 23, 2010 at 21:23 UTC
I tried your code but it doesn't give the capabilities to do up and down for the history which is what the op wanted.	[reply]
Re^3: Simulating Command Line History in Perl by almut (Canon) on Apr 23, 2010 at 21:59 UTC
Works for me. I.e., type "foo" at the prompt, followed by <Enter>. New empty prompt appears. Hit cursor up, and "foo" is back for you to edit. This is what I understood the OP wanted... If that doesn't work, you're likely either on Windows, or don't have Term::ReadLine::Gnu installed.	[reply]
Re^4: Simulating Command Line History in Perl by Anonymous Monk on Apr 23, 2010 at 22:40 UTC
It still doesn't work for me... I have Term::ReadLine::Gnu installed.	[reply]
Re^5: Simulating Command Line History in Perl by bichonfrise74 (Vicar) on Apr 23, 2010 at 22:42 UTC
Re^3: Simulating Command Line History in Perl by rowdog (Curate) on Apr 23, 2010 at 22:07 UTC
Term::ReadLine will pick from a number of different backends depending on what's available. My custom built perl finds Term::ReadLine::Gnu and works just fine. My system perl, which I never touch, found Term::ReadLine::Stub which does not work correctly, because it's just a stub. Add this line to almut's code to see your backend. `print "Using ", $term->ReadLine, "\n";` [download]	[reply] [d/l]
Re^2: Simulating Command Line History in Perl by Only1KW (Sexton) on Apr 23, 2010 at 21:22 UTC
Like I said, I understand that ReadLine can get the history...that's the easy part. What methods on, say, Term::ReadLine::Gnu, will put the output back on the screen for the user to edit?	[reply]
Re^3: Simulating Command Line History in Perl by Only1KW (Sexton) on Apr 23, 2010 at 21:40 UTC
Nm, I see about the second argument now. It seems to be working now. Thanks. Just wish the ReadLine help text were more verbose about this.	[reply]
Re^4: Simulating Command Line History in Perl by almut (Canon) on Apr 24, 2010 at 07:28 UTC
I see about the second argument now Just to be clear, the second argument is not for implementing a command history; it's for prompting with some default input as, for example, in install/configure scripts `... In which directory would you like the package to be installed? > /usr/local/foo` [download] where the editable input `"/usr/local/foo"` would appear at the prompt immediately, as a suggested default choice, without the user having to hit any cursor up/down keys etc. Implementing a history via that feature would be quite cumbersome, as you'd have to read out the respective history entries yourself and present a new prompt for each entry... With GNU readline the history is basic functionality, which should work without further ado, if you have the right backend module installed.	[reply] [d/l] [select]