Perl

Start a Remote Shell with QuickShell

Demonstrates the Chilkat Ssh.QuickShell method, which starts a remote shell using the simplified sequence OpenSessionChannel → SendReqPty → SendReqShell. It takes no arguments and returns the shell channel number, or -1 on failure. The default PTY size is 80 columns by 24 rows.

Background: Note that QuickShell does allocate a PTY, so unlike a bare SendReqShell the remote shell runs interactively: it prints a command prompt, echoes the commands you send, and runs interactive login scripts. That is convenient for terminal-style work but means the output contains prompts and echoed input that scripted parsing must tolerate. The method returns as soon as the shell request is accepted — it does not consume the initial login text or prompt, so read and discard that before relying on command output.

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Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# Demonstrates the Ssh.QuickShell method, which starts a remote shell using the simplified
# sequence OpenSessionChannel, SendReqPty, and SendReqShell.  It takes no arguments and returns
# the shell channel number, or -1 on failure.  The default PTY size is 80 columns by 24 rows.

my $ssh = Chilkat2::Ssh->new;

my $sshPort = 22;
my $success = $ssh->Connect('ssh.example.com', $sshPort);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# Normally you would not hard-code the password in source.  You should instead obtain it
# from an interactive prompt, environment variable, or a secrets vault.
my $password = 'mySshPassword';

$success = $ssh->AuthenticatePw('mySshLogin', $password);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# Start the shell.  Note that QuickShell allocates a PTY, so the remote shell runs
# interactively: it prints a command prompt and echoes the commands that are sent to it.
my $channelNum = $ssh->QuickShell();
if ($channelNum < 0) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# QuickShell returns as soon as the shell request is accepted -- it does not wait for or
# consume the initial login text or prompt.
$success = $ssh->ChannelSendString($channelNum, "uname -a; echo DONE_MARKER\n", 'utf-8');
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
# which means no limit -- without it, this call waits forever if the received data never
# contains a match.
$ssh->ReadTimeoutMs(15000);

my $caseSensitive = 0;
$success = $ssh->ChannelReceiveUntilMatch($channelNum, 'DONE_MARKER', 'utf-8', $caseSensitive);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

my $output = $ssh->GetReceivedText($channelNum, 'utf-8');
if (!$ssh->LastMethodSuccess) {
    print $ssh->LastErrorText, "\n";
    exit;
}

print $output, "\n";

$ssh->Disconnect();