(Perl) SSH Remote Shell

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$ssh = chilkat::CkSsh->new();

# Hostname may be an IP address or hostname:
$hostname = "www.some-ssh-server.com";
$port = 22;

# Connect to an SSH server:
$success = $ssh->Connect($hostname,$port);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Wait a max of 5 seconds when reading responses..
$ssh->put_IdleTimeoutMs(5000);

# Authenticate using login/password:
$success = $ssh->AuthenticatePw("myLogin","myPassword");
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Open a session channel.  (It is possible to have multiple
# session channels open simultaneously.)

$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Some SSH servers require a pseudo-terminal
# If so, include the call to SendReqPty.  If not, then 
# comment out the call to SendReqPty.
# Note: The 2nd argument of SendReqPty is the terminal type,
# which should be something like "xterm", "vt100", "dumb", etc.
# A "dumb" terminal is one that cannot process escape sequences.
# Smart terminals, such as "xterm", "vt100", etc. process
# escape sequences.  If you select a type of smart terminal,
# your application will receive these escape sequences
# included in the command's output.  Use "dumb" if you do not
# want to receive escape sequences.  (Assuming your SSH
# server recognizes "dumb" as a standard dumb terminal.)
$termType = "dumb";
$widthInChars = 120;
$heightInChars = 40;
# Use 0 for pixWidth and pixHeight when the dimensions
# are set in number-of-chars.
$pixWidth = 0;
$pixHeight = 0;
$success = $ssh->SendReqPty($channelNum,$termType,$widthInChars,$heightInChars,$pixWidth,$pixHeight);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Start a shell on the channel:
$success = $ssh->SendReqShell($channelNum);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Start a command in the remote shell.  This example
# will send a "ls" command to retrieve the directory listing.
$success = $ssh->ChannelSendString($channelNum,"ls\r\n","ansi");
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Send an EOF.  This tells the server that no more data will 
# be sent on this channel.  The channel remains open, and
# the SSH client may still receive output on this channel.
$success = $ssh->ChannelSendEof($channelNum);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Read whatever output may already be available on the
# SSH connection.  ChannelReadAndPoll returns the number of bytes
# that are available in the channel's internal buffer that
# are ready to be "picked up" by calling GetReceivedText
# or GetReceivedData.
# A return value of -1 indicates failure.
# A return value of -2 indicates a failure via timeout.

# The ChannelReadAndPoll method waits
# for data to arrive on the connection usingi the IdleTimeoutMs
# property setting.  Once the first data arrives, it continues
# reading but instead uses the pollTimeoutMs passed in the 2nd argument:
# A return value of -2 indicates a timeout where no data is received.

$pollTimeoutMs = 2000;
$n = $ssh->ChannelReadAndPoll($channelNum,$pollTimeoutMs);
if ($n < 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Close the channel:
$success = $ssh->ChannelSendClose($channelNum);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Perhaps we did not receive all of the commands output.
# To make sure,  call ChannelReceiveToClose to accumulate any remaining
# output until the server's corresponding "channel close" is received.
$success = $ssh->ChannelReceiveToClose($channelNum);
if ($success != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Let's pickup the accumulated output of the command:
$cmdOutput = $ssh->getReceivedText($channelNum,"ansi");
if ($ssh->get_LastMethodSuccess() != 1) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

# Display the remote shell's command output:
print $cmdOutput . "\r\n";

# Disconnect
$ssh->Disconnect();