(Ruby) SSH Remote Shell Multiple Commands

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

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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

ssh = Chilkat::CkSsh.new()

# This is the prompt we'll be expecting to find in
# the output of the remote shell.

myPrompt = "chilkat@ubuntu:~/workspace$"

# Connect to an SSH server:

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

success = ssh.Connect(hostname,port)
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# Wait a max of 10 seconds when reading responses..
ssh.put_IdleTimeoutMs(10000)

# Authenticate using login/password:
success = ssh.AuthenticatePw("myLogin","myPassword")
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

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

channelNum = ssh.OpenSessionChannel()
if (channelNum < 0)
    print ssh.lastErrorText() + "\n";
    exit
end

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 != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# Start a shell on the channel:
success = ssh.SendReqShell(channelNum)
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

#  Run the 1st command in the remote shell, which will be to
#  "cd" to a subdirectory.
success = ssh.ChannelSendString(channelNum,"cd workspace\r\n","ansi")
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# Retrieve the output.
success = ssh.ChannelReceiveUntilMatch(channelNum,myPrompt,"ansi",true)
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

#  Display what we've received so far.  This clears
#  the internal receive buffer, which is important.
#  After we send the command, we'll be reading until
#  the next command prompt.  If the command prompt
#  is already in the internal receive buffer, it'll think it's
#  already finished...
cmdOutput = ssh.getReceivedText(channelNum,"ansi")
if (ssh.get_LastMethodSuccess() != true)
    print ssh.lastErrorText() + "\n";
    exit
end

print cmdOutput + "\n";

#  Run the 2nd command in the remote shell, which will be
#  to "ls" the directory.
success = ssh.ChannelSendString(channelNum,"ls\r\n","ansi")
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# Retrieve and display the output.
success = ssh.ChannelReceiveUntilMatch(channelNum,myPrompt,"ansi",true)
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

cmdOutput = ssh.getReceivedText(channelNum,"ansi")
if (ssh.get_LastMethodSuccess() != true)
    print ssh.lastErrorText() + "\n";
    exit
end

print cmdOutput + "\n";

#  Start the final command in the remote shell.  This example
#  will send a "ls -l" command to retrieve the long format directory listing.
success = ssh.ChannelSendString(channelNum,"ls -l\r\n","ansi")
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# 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 != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# 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() + "\n";
    exit
end

# Close the channel:
success = ssh.ChannelSendClose(channelNum)
if (success != true)
    print ssh.lastErrorText() + "\n";
    exit
end

# 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 != true)
    print ssh.lastErrorText() + "\n";
    exit
end

cmdOutput = ssh.getReceivedText(channelNum,"ansi")
if (ssh.get_LastMethodSuccess() != true)
    print ssh.lastErrorText() + "\n";
    exit
end

print cmdOutput + "\n";

# Disconnect
ssh.Disconnect()