alternative for netcat utility - linux

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\r\n" | nc -U /var/run/docker.sock

Answer 1

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 2

socat is a more powerful version of nc and netcat.

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