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$ rpcinfo 
   program version netid     address                service    owner
    100000    4    tcp6      ::.0.111               portmapper superuser
    100000    3    tcp6      ::.0.111               portmapper superuser
    100000    4    udp6      ::.0.111               portmapper superuser
    100000    3    udp6      ::.0.111               portmapper superuser
    100000    4    tcp       0.0.0.0.0.111          portmapper superuser
    100000    3    tcp       0.0.0.0.0.111          portmapper superuser
    100000    2    tcp       0.0.0.0.0.111          portmapper superuser
    100000    4    udp       0.0.0.0.0.111          portmapper superuser
    100000    3    udp       0.0.0.0.0.111          portmapper superuser
    100000    2    udp       0.0.0.0.0.111          portmapper superuser
    100000    4    local     /run/rpcbind.sock      portmapper superuser
    100000    3    local     /run/rpcbind.sock      portmapper superuser

How can I get the manpage-like help information of a service?

$ man portmapper
No manual entry for portmapper

How can I find out the actual program/executable/command name for a RPC service? For example portmapper isn't a command name for portmapper RPC service, otherwise man portmapper would likely works.

Thanks.

炸鱼薯条德里克
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Tim
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  • Did you mean systemd service? Why this is not included in the question? If yes, look at the .service files. Or just use `systemctl cat xxx.service` which follow systemd unit file override rules. – 炸鱼薯条德里克 Mar 21 '19 at 03:35
  • "portmapper isn't a command name for portmapper service, otherwise man portmapper would likely works" Notice Developer can freely choose the name of the command and the name of the man page entry. Also notice shells can have alias for commands. – 炸鱼薯条德里克 Mar 21 '19 at 03:38
  • @炸鱼薯条德里克 better yet, for a systemd service you can try `systemctl help`. But this is RPC so it’s not systemd services. – Stephen Kitt Mar 21 '19 at 05:15
  • @StephenKitt Sorry for my previous comment (deleted). I meant `systemctl help nfs-service` and `systemctl help nfs-kernel-service` don't output anything – Tim Mar 21 '19 at 16:02
  • @Tim right, unfortunately the unit files don’t have `Documentation=` keys so `systemctl help` doesn’t output anything. – Stephen Kitt Mar 21 '19 at 16:06

1 Answers1

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In some cases, apropos (or man -k) will find the relevant manpage. That’s not the case here, but a full-text search using man -K will lead to the rpcinfo(8) manpage which says that

Version 2 of the rpcbind protocol was previously known as the portmapper protocol.

So the command you’re looking for is rpcbind.

Stephen Kitt
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  • "So the command you’re looking for is rpcbind." do you mean rpcinfo instead? – Tim Mar 21 '19 at 16:50
  • No, the `rpcinfo` manpage mentions `rpcbind`, which is how one ends up looking at `rpcbind` and realising that that’s the program which implements the portmapper service (which answers the last part of your question). – Stephen Kitt Mar 21 '19 at 16:59