PHP

SSH Exec (Execute Command Line)

Demonstrates running a single command on an SSH server with an exec request and retrieving its output. The example connects, authenticates, opens a session channel, sends the command, reads until the server closes the channel, and then checks the exit status.

Background: exec is the workhorse of SSH automation: it runs one command and the server closes the channel when the command exits, which is a definitive end-of-output signal. No PTY is involved, so the shell runs non-interactively — no prompt, no echoed input, no ANSI escape codes — giving clean, parseable output. Remember that an accepted exec request only means the request was accepted; the command's own success is reported through the channel exit status. Command syntax depends on the remote shell, which is the user's default shell on Linux/UNIX and usually CMD.EXE on Windows SSH servers.

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<?php

use Chilkat2\Ssh;

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Demonstrates running a single command on an SSH server with an exec request and retrieving
// its output.  An exec request runs one command and the server closes the channel when it
// finishes -- no PTY and no shell prompt are involved, so the output is clean and parseable.

$ssh = new Ssh();

// The hostname may be a hostname or an IP address.
$hostname = 'ssh.example.com';
$port = 22;
try {
    $ssh->Connect($hostname, $port);

    // 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.
    $password = 'mySshPassword';

    $ssh->AuthenticatePw('mySshLogin', $password);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Open a session channel.  Several session channels may be open at once on one connection.
$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    echo $ssh->LastErrorText, "\n";
    exit;
}

// The command syntax depends on the remote system's shell.  On Linux/UNIX it is typically the
// user's default shell; on Windows SSH servers it is usually CMD.EXE.
//   Linux/UNIX:  "ls -l /tmp"        or  "cd /etc; ls -la"
//   Windows:     "dir"               or  "\"cd \\temp&&dir\""
try {
    $ssh->SendReqExec($channelNum, 'ls -l /tmp');

    // IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    // it, this call waits forever if the server never sends channel close.
    $ssh->ReadTimeoutMs = 15000;

    // Read the output until the server sends channel close, which happens when the command exits.
    $ssh->ChannelReceiveToClose($channelNum);

    $cmdOutput = $ssh->GetReceivedText($channelNum, 'utf-8');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $cmdOutput, "\n";

// An accepted exec request does not mean the command succeeded.  Check the exit status.
if ($ssh->ChannelReceivedExitStatus($channelNum)) {
    echo 'Exit status: ', $ssh->GetChannelExitStatus($channelNum), "\n";
}

$ssh->Disconnect();