Let install hint the user to do init.

lib/App/Perlbrew/Path.pm

@@ -38,6 +38,12 @@ sub new {
     bless { path => _joinpath (@path) }, $class;
 }
 
+sub exists {
+    my ($self) = @_;
+
+    -e $self->stringify;
+}
+
 sub basename {
     my ($self, $suffix) = @_;
 

lib/App/perlbrew.pm

@@ -1282,6 +1282,10 @@ sub do_install_release {
 sub run_command_install {
     my ($self, $dist, $opts) = @_;
 
+    unless ($self->root->exists) {
+        die("ERROR: perlbrew root " . $self->root . " does not exist. Run `perlbrew init` to prepare it first.\n");
+    }
+
     unless ($dist) {
         $self->run_command_help("install");
         exit(-1);

t/12.destdir.t

@@ -12,12 +12,6 @@ my $DESTDIR = tempdir( CLEANUP => 1 );
 
 use Test::More;
 
-## setup
-
-App::Perlbrew::Path
-    ->new($ENV{PERLBREW_ROOT})
-    ->rmpath;
-
 ## mock
 
 no warnings 'redefine';

t/12.sitecustomize.t

@@ -11,12 +11,6 @@ $ENV{PERLBREW_ROOT} = $App::perlbrew::PERLBREW_ROOT;
 
 use Test::More;
 
-## setup
-
-App::Perlbrew::Path
-    ->new ($ENV{PERLBREW_ROOT})
-    ->rmpath;
-
 ## mock
 
 no warnings 'redefine';

t/error-install-before-init.t

@@ -0,0 +1,24 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use Test::More;
+use Test::Exception;
+use File::Temp qw(tempdir);
+
+use App::perlbrew;
+use App::Perlbrew::Path;
+
+my $fakehome = tempdir( CLEANUP => 1 );
+
+$ENV{PERLBREW_ROOT} = $App::perlbrew::PERLBREW_ROOT = App::Perlbrew::Path->new($fakehome)->child("perl5")->stringify;
+
+throws_ok(
+    sub {
+        my $app = App::perlbrew->new("install", "perl-5.36.0");
+        $app->run;
+    },
+    qr[ERROR: .*perlbrew init.*]
+);
+
+done_testing;