alternative for netcat utility

Question

Is there any alternative for netcat utility? I want to run docker API and netcat utility is not installed on client system. docker command example - echo -e \"GET /info HTTP/1.0

Answer 1

socat is a more powerful version of nc and netcat.

Answer 2

According to this,

(exec 3<>/dev/tcp/url/port; cat >&3; cat <&3; exec 3<&-)

can replace nc/netcat. It should work in any bash based terminal.

Example:

printf "Hello World!" | (exec 3<>/dev/tcp/termbin.com/9999; cat >&3; cat <&3; exec 3<&-)

returns a link.

Answer 3

Have you got Perl? You could do something like this maybe:

perl -MLWP::Simple -e "getprint('http://localhost')"

Answer 4

Follow a implementation in Python for making sockets connections and sending data in tcp and udp:

import socket

def netcat(hostname, port, content=None, protocol='tcp'):
    print('')
    if protocol == 'tcp':
        s = socket.socket() # (socket.AF_INET, socket.SOCK_STREAM)
    if protocol == 'udp':
        s = socket.socket(family=socket.AF_INET, type=socket.SOCK_DGRAM)
    if protocol != 'tcp' and protocol != 'udp':
        print("Error: Protocol must be 'tcp' or 'udp'")
    try:
        s.connect((hostname, port))
        print('Connection Success to ' + hostname + ':' + str(port) + '/' + protocol)
    except:
        print('Connection failed to ' + hostname + ':' + str(port) + '/' + protocol)
        return None
    if content != None:
        print('Starting to send content: ' + str(content))
        s.send(str.encode(content))
        # s.sendall(content)
        hasHacievedAnyData = False
        while True:
            s.settimeout(10)
            try:
                data = s.recv(1024)
            except Exception:
                if hasHacievedAnyData:
                    print('Info: Timeout while expecting to receve more data')
                else:
                    print('Error: Timeout while expecting to receve data')
                break
            if len(data) == 0:
                break
            print('Received:' + str(repr(data)))
            hasHacievedAnyData = True
        s.shutdown(socket.SHUT_WR)
        s.close()
        print('Connection closed.')

#Examples of usage
netcat('localhost', 443)
netcat('localhost', 3478)
netcat('localhost', 3478, protocol='udp')
netcat('localhost', 16384, 'Hello', 'udp')

Answer 5

Python is ubiquitous these days and the socket module is all you need.

Here are a few examples: You can use it to test connectivity on port 443 to a list of 3 hosts:

import socket

def test_socket(ip,port):
        s = socket.socket()

        try:
            s.settimeout(3)
            s.connect((ip,port))
        except socket.error as msg:
            s.close()
            print 'could not open %s:%s %s' % (ip,port,msg)
            return(1)
        else:
            s.close()
            print '%s:%s is OK' % (ip,port)
            return(0)


hosts=['host1.example.com','host2.example.com','host3.example.com']

for host in hosts:
   print "testing %s 443" % host
   test_socket(host,443)

This one liner can read stdin or files and send to hostname termbin.com on port 9999 upload a file to termbin:

 python -c "import socket,fileinput;  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM); s.connect(('termbin.com', 9999)) ; [ s.send(b) for b in fileinput.input() ]; print s.recv(1024); s.close();" filetoupload.txt