gmdns(1)

🌸 gmdns — bestie's guide to the mDNS tool 💅

okay so welcome to gmdns(1), section 1 of the manual, and let me just say — this little icon is a tool for doing mDNS operations, and if you don't know what that means yet, don't even worry, we're getting there together 🫶

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✨ NAME ✨

gmdns — the tool for doing mDNS operations. that's it. that's the name. short, sweet, main character energy 💖

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🌈 SYNOPSIS 🌈

gmdns [-n|--name str] [-t|--type str] [-m|--domain str] [-o|--host str]
[-i|--interface num] [-y|--nettype unspec|ipv4|ipv6] [-s|--service]
[-x|--txt str] [-p|--port num] [-c|--close-on-done] [--timeout
time_in_msecs] [-d|--debug] [-h|--help]

no cap, that's the whole vibe right there. every bracket is optional, every | is "pick a lane bestie" ⭐

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🦋 DESCRIPTION 🦋

so like. the gmdns program lets you do exactly two things, and both of them are iconic:

• advertise an mDNS service 🔥
• query for mDNS services on the local network 👑

that's the tea. one binary, two moods, zero drama ✨

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💅 OPTIONS 💅

every flag, every default, nothing skipped, because we don't gatekeep here:

• -n, --name str — the name field for the service/query. literally its name. give it a name 🎀
• -t, --type str — the type field for the service/query. like _http._tcp energy, you know the drill ✨
• -m, --domain str — the domain field for the service/query. the domain. yes queen 🌸
• -o, --host str — the host field for the service/query. who's hosting? this one 🫶
• -i, --interface num — the interface number for the service/query. if it's -1, you're service/querying all the interfaces on the system. defaults to -1. so like, the default is "everybody's invited" 💖
• -y, --nettype unspec|ipv4|ipv6 — the network type for the service/query. if it's unspec, the service/query is for IPv4 and IPv6 both, bestie, why choose. otherwise it's only for the protocol you specified. defaults to unspec. slay 🌈
• -s, --service — advertise a network service instead of doing a query. in this case, name, type, and port must be provided — non-negotiable, it's giving mandatory. the others are optional and should not be provided unless you actually need them, so don't just fill in every field for fun 🙈
• -x, --txt str — add the string to the set of text strings advertised for a service. only makes sense with -s. periodt 🎀
• -p, --port str — use the given port for the advertised service. only make sense with -s 💅
• -c, --close-on-done — for a query: after all currently known services are reported, exit. like, we got what we came for, we're leaving, bye 👋
• --timeout time — the amount of time to wait, in milliseconds, before closing everything and terminating. it's a countdown bestie, tick tock ⏳
• -d, --debug — generate debugging output. specifying it more than once increases the output. stack it, layer it, go feral with it 🔍
• -h, --help — help output. the classic. the icon 👑

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🔍 STRING VALUES FOR QUERIES 🔍

okay this is the part where it gets spicy, pay attention 🌶️

the string values for queries may use regular expressions or globs. here's the cheat sheet:

• if the string starts with '%', then the data after it is treated as a regular expression, and fields are matched against that. see regex(7) for the details 📖
• if the string starts with '@', then the data after it is treated as a standard glob. see glob(7) for the details 🌐
• if the string starts with '=', an exact comparison is done with the data after it ✅
• if the string starts with a-z0-9_ or a space, then an exact string comparison is done, including the first character — so yeah, that leading char counts, don't forget it 🫠

and now the scary part: the behavior of matching for any other starting character is undefined. undefined!! not "probably fine", not "works most of the time" — undefined. so in general, you should always use '@', '%', or '=' as the starting character of all your query strings to be sure. i'm literally begging you 🙏

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👀 SEE ALSO 👀

go read your siblings, they're all iconic too:

• gensio_mdns(3)
• regex(7)
• glob(7)

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💀 KNOWN PROBLEMS 💀

None.

yes bestie, that's the whole section. not one single problem. flawless behavior. no bugs, only vibes 🧚

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👑 AUTHOR 👑

Corey Minyard <minyard@acm.org> — the legend, the moment, the whole reason we're here 💜

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and that's the page!! this came out of the 2020 edition of the gmdns(1) manual, dated Oct 15 — so if you're reading this, shoutout to the source and version, and remember: always use '@', '%', or '=' in your query strings, and never start one with a random character. bye bestie, go mDNS responsibly 💖✨🎀🦋🌸