NANOCAT(1)

📦
version 1.2.2 · 10 versions
, in fedora 44

🎀 NANOCAT 🎀

okay bestie, sit down, hydrate, and let me tell you about nanocat(1) — she's the command-line girlie from nanomsg version 1.2.2, and she is lowkey iconic. if you've ever wanted to yeet data across a network from your shell like it's nothing, this is your moment. ✨

💖 NAME 💖

nanocat — a command-line interface to nanomsg. that's the whole vibe. 🫶

✨ SYNOPSIS ✨

the main-character lineup, one per socket type:

nanocat --req {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nanocat --rep {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-AQ]
nanocat --push {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC]
nanocat --pull {--connect ADDR|--bind ADDR} [-AQ]
nanocat --pub {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC]
nanocat --sub {--connect ADDR|--bind ADDR} [--subscribe PREFIX ...] [-AQ]
nanocat --surveyor {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nanocat --respondent {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-AQ]
nanocat --bus {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nanocat --pair {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]

and if the symlinks happen to be installed, you get these glow-up short names instead — same energy, fewer letters:

nn_req {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nn_rep {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-AQ]
nn_push {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC]
nn_pull {--connect ADDR|--bind ADDR} [-AQ]
nn_pub {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC]
nn_sub {--connect ADDR|--bind ADDR} [--subscribe PREFIX ...] [-AQ]
nn_surveyor {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nn_respondent {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-AQ]
nn_bus {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]
nn_pair {--connect ADDR|--bind ADDR} {--data DATA|--file PATH} [-i SEC] [-AQ]

🌈 DESCRIPTION 🌈

so nanocat is a command-line tool for sending and receiving data through nanomsg sockets. that's it. that's her job and she does it flawlessly. 💅

and like, what do you do with that? the manpage says: debugging (obvi), sending files through the network (yes really), health checking the system (she's a doctor too), or honestly whatever else you can think of — the limit is literally your imagination, bestie. 🦋

🔥 OPTIONS 🔥

🌸 Generic 🌸

  • --verbose, -v — crank the verbosity of the nanocat up. more talking, more details.
  • --silent, -q — drop the verbosity of the nanocat down. shhh, she's being mysterious. 🤫
  • --help, -h — this help text. she explains herself when asked.

🌟 Socket Types 🌟

pick your girl. one of these, please:

  • --push — use NN_PUSH socket type
  • --pull — use NN_PULL socket type
  • --pub — use NN_PUB socket type
  • --sub — use NN_SUB socket type
  • --req — use NN_REQ socket type
  • --rep — use NN_REP socket type
  • --surveyor — use NN_SURVEYOR socket type
  • --respondent — use NN_RESPONDENT socket type
  • --bus — use NN_BUS socket type
  • --pair — use NN_PAIR socket type

🔌 Socket Options 🔌

  • --bind ADDR — bind the socket to the address ADDR
  • --connect ADDR — connect the socket to the address ADDR
  • --bind-ipc, -X PATH — bind the socket to the ipc address "ipc://PATH".
  • --connect-ipc, -x PATH — connect the socket to the ipc address "ipc://PATH".
  • --bind-local, -L PORT — bind the socket to the tcp address "tcp://127.0.0.1:PORT".
  • --connect-local, -l PORT — connect the socket to the tcp address "tcp://127.0.0.1:PORT".
  • --recv-timeout SEC — set the timeout for receiving a message
  • --send-timeout SEC — set the timeout for sending a message

🎧 SUB Socket Options 🎧

  • --subscribe PREFIX — subscribe to the prefix PREFIX. note: the socket will be subscribed to everything (that's an empty prefix) if no prefixes are specified on the command-line. she's a yes-girl by default, periodt.

📥 Input Options 📥

  • --format FORMAT — use echo format FORMAT (same as the options below)
  • --raw — dump the message as is. (note: no delimiters are printed)
  • --ascii, -A — print the ASCII part of the message delimited by newline. all non-ascii characters get replaced by a dot.
  • --quoted, -Q — print each message on a separate line in double quotes with C-like character escaping
  • --msgpack — print each message as a msgpacked string (raw type). this one's for the girlies doing programmatic parsing 💻

📤 Output Options 📤

  • --interval, -i SEC — send a message (or a request) every SEC seconds. she's consistent. she's reliable. she's that girl.
  • --delay, -d SEC — wait SEC seconds before sending the message (super useful for one-shot PUB sockets)
  • --data, -D DATA — send DATA to the socket and quit, for PUB, PUSH, PAIR, BUS sockets. use DATA to reply for REP or RESPONDENT sockets. send DATA as a request for REQ or SURVEYOR sockets. one flag, three whole personalities. 💅
  • --file, -F PATH — same as --data but it gets the data from the file PATH

🌸 EXAMPLES 🌸

the classic ping-pong with nn_req/nn_rep sockets — and bestie, these must be run simultaneously, no cap, two terminals or it's not happening:

nanocat --rep --bind tcp://127.0.0.1:1234 --data pong --format ascii
nanocat --req --connect tcp://127.0.0.1:1234 --data ping --format ascii

or, if you want the shorter-to-write form, she also comes in snack size:

nn_rep -L1234 -Dpong -A
nn_req -l1234 -Dping -A

do periodic requests, once every second, like clockwork 🕐:

nn_req -l1234 -Dping -A -i 1

the rep socket that never replies (that's the no--D-option lifestyle) — this one is genuinely useful for checking whether the resending of requests is actually working:

nanocat --rep --connect ipc:///var/run/app/req.socket

send the output of ls to whatever would connect to 127.0.0.1:1234 and then dip:

ls | nanocat --push -L1234 -F-

and finally, send heartbeats to an imaginary monitoring service, because even fictional infrastructure deserves love 💖:

nanocat --pub --connect tcp://monitoring.example.org -D"I am alive!" --interval 10

👀 SEE ALSO 👀

nanomsg(7) — go read the big one, she's the parent lore.

👑 AUTHORS 👑

Paul Colomiets <paul@colomiets.name> — the icon, the legend, the one who made her. 🌟

and that's the whole page, bestie! this was nanocat(1) from nanomsg version 1.2.2, dated 2026-01-16. go forth and socket responsibly. 🎀✨💅🦋

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