NAME

ncat - network aware cat

SYNOPSIS

DESCRIPTION

ncat concatenates data streams similar to cat(1) except the streams can be files or TCP connections. If no streams are given on the command line ncat will default to reading from standard input and writing to standard output.

There are several different forms for specifying a stream:

filename or filename:: Any filename containing a colon needs to be escaped by adding a colon on the end, otherwise it will be interpreted as a tcp stream. A special filename "-" can be used to specify standard input or output.
host:port: Connect to host/port. This will fail if the remote side is not ready for the connection.
:port: Wait for a connection on port. This can block indefinitely. If port is 0 (or omitted) ncat will bind to a free port and display the port used on standard error.

OPTIONS

-o, --output

Output to stream instead of standard output.

-b, --block-size

Use a different block size for reading and writing. The default is 512 bytes. size can be given a suffix to denote a multiplier: b for 512 , k for 1024, m for 1024k.

-v, --verbose

Show data transfer statistics.

-n, --no-delay

Disable buffering and merging small tcp packets. This can reduce latency in some situations.

-c, --cork

Prevent TCP from sending partial packets across the network until the connections is closed. This breaks compatibility with cat by not passing data on immediately, but it may improve performance depending on your requirements. Linux 2.2+ is required to use this option.

-V, --version

Display version and exit.

-h, --help

Display usage information and exit.

EXIT STATUS

0: Success
1: One or more errors occured reading data and ncat continued onto the next stream.
255: A fatal error occured writing data.

BUGS

Some rarely used options found in cat(1) are missing from ncat. These options can be recreated easily by using another filter such as perl(1), awk(1), sed(1), or tr(1).

AUTHOR

Mark Pulford <mark@kyne.com.au>