4 ms·

I guess at this point I'm never going to learn the difference between rlogin, rsh, and rexec. Even googling it and reading the first page of results doesn't cle

by raldi 9y ago

I guess at this point I'm never going to learn the difference between rlogin, rsh, and rexec. Even googling it and reading the first page of results doesn't clear things up.

killerbat00 9y ago
A comment below explains exactly this: https://news.ycombinator.com/item?id=14699219 https://news.ycombinator.com/item?id=14699219
- raldi 9y ago
  No it doesn't. It explains what the three as a group do; what I'm asking is, what's the difference between these three? Why did we need three separate commands? When (in the pre-SSH days) would you use one versus the others?
  - the_mitsuhiko 9y ago
    SSH also brings these separate commands and a few more. ssh, slogin, scp, sshd, and sftp.
    - raldi 9y ago
      Okay, but that's not the question I'm asking.
      - sigjuice 9y ago
        Each of these FreeBSD commands have man pages which your googling should have shown.
        raldi 9y ago
        slogin is just a symlink to ssh, and sexec does not exist. So the s-commands' manpages tell me nothing about the difference between rsh, rlogin, and rexec, or why all three needed to be created.
        sigjuice 9y ago
        rsh, rlogin and rexec each have their own man pages, which you should be able to find on freebsd.org if google is being difficult.
        raldi 9y ago
        Right. They say that rsh can be used to get a login or run a command on a remote host. So why do the other two commands exist? In what situations would a person have wanted to use rlogin or rexec instead of rsh?
        sigjuice 9y ago
        Maybe rexec appeared first? And when rsh arrived later, they still kept rexec around? Perhaps they had a lot of shell scripts that contained "rexec" and didn't want to bother changing them to "rsh"? The actual reason is probably so mundane that maybe there is no accurate historical information on this topic.
        JdeBP 9y ago
        The irony here is that these manual pages are the very things being patched in the headlined message. Their exact locations in the source tree, and some of their contents, are right there in front of us.
        sigjuice 9y ago
        So read the older man pages? Why is this a problem? You can also easily read the man pages for a specific version of FreeBSD here https://www.freebsd.org/cgi/man.cgi https://www.freebsd.org/cgi/man.cgi
  - yrro 9y ago
    I'd assume rexec runs a command on a remote host non interactively; rsh runs an interactive shell on a remote host; and rlogin allows you to interact with login(1), again on a remote host. But I've not read the man pages as I'm on my phone.
deleted 9y ago
[deleted]
reacweb 9y ago
rlogin's aim is to open an interactive session with a remote host. rsh can do that also but is mainly used to run a command remotely. Access control is generally configured on the remote host using a file named .rhosts. If there is no authorisation in .rhosts, rlogin will ask for the password. rexec is used to launch a remote command using a login and a password. For convenience, these passwords can be stored locally in a file named .netrc.
tyingq 9y ago
==Rsh vs rlogin== Rsh was made to run a remote command without a login shell. Like rsh remotehost <command>. If you omit <command> rsh does an execv() of rlogin. ==Rsh vs Rexec== Rexec allows you to specify a password on the command line, rsh does not...it expects you to either use .rhosts, or enter the password interactively. Rexec also doesn't have the functionality where it invokes rlogin if you omit the command...the command is mandatory. ==Why?== No idea. Yes, it's odd that it wasn't all made as a single client binary. There were also different daemons on the server side...rexecd, rshd, rlogind. Also fun, there was often another binary called rsh that had nothing to do with this rsh or remote logins. It was a restricted login shell so that you could have limited rights users.

by raldi 9y ago

I guess at this point I'm never going to learn the difference between rlogin, rsh, and rexec. Even googling it and reading the first page of results doesn't clear things up.

killerbat00 9y ago

A comment below explains exactly this: https://news.ycombinator.com/item?id=14699219 https://news.ycombinator.com/item?id=14699219

raldi 9y ago
No it doesn't. It explains what the three as a group do; what I'm asking is, what's the difference between these three? Why did we need three separate commands? When (in the pre-SSH days) would you use one versus the others?
- the_mitsuhiko 9y ago
  SSH also brings these separate commands and a few more. ssh, slogin, scp, sshd, and sftp.
  - raldi 9y ago
    Okay, but that's not the question I'm asking.
    - sigjuice 9y ago
      Each of these FreeBSD commands have man pages which your googling should have shown.
      - raldi 9y ago
        slogin is just a symlink to ssh, and sexec does not exist. So the s-commands' manpages tell me nothing about the difference between rsh, rlogin, and rexec, or why all three needed to be created.
        sigjuice 9y ago
        rsh, rlogin and rexec each have their own man pages, which you should be able to find on freebsd.org if google is being difficult.
        raldi 9y ago
        Right. They say that rsh can be used to get a login or run a command on a remote host. So why do the other two commands exist? In what situations would a person have wanted to use rlogin or rexec instead of rsh?
        sigjuice 9y ago
        Maybe rexec appeared first? And when rsh arrived later, they still kept rexec around? Perhaps they had a lot of shell scripts that contained "rexec" and didn't want to bother changing them to "rsh"? The actual reason is probably so mundane that maybe there is no accurate historical information on this topic.
        JdeBP 9y ago
        The irony here is that these manual pages are the very things being patched in the headlined message. Their exact locations in the source tree, and some of their contents, are right there in front of us.
        sigjuice 9y ago
        So read the older man pages? Why is this a problem? You can also easily read the man pages for a specific version of FreeBSD here https://www.freebsd.org/cgi/man.cgi https://www.freebsd.org/cgi/man.cgi
- yrro 9y ago
  I'd assume rexec runs a command on a remote host non interactively; rsh runs an interactive shell on a remote host; and rlogin allows you to interact with login(1), again on a remote host. But I've not read the man pages as I'm on my phone.

deleted 9y ago

[deleted]

reacweb 9y ago

rlogin's aim is to open an interactive session with a remote host. rsh can do that also but is mainly used to run a command remotely. Access control is generally configured on the remote host using a file named .rhosts. If there is no authorisation in .rhosts, rlogin will ask for the password. rexec is used to launch a remote command using a login and a password. For convenience, these passwords can be stored locally in a file named .netrc.

tyingq 9y ago

==Rsh vs rlogin== Rsh was made to run a remote command without a login shell. Like rsh remotehost <command>. If you omit <command> rsh does an execv() of rlogin. ==Rsh vs Rexec== Rexec allows you to specify a password on the command line, rsh does not...it expects you to either use .rhosts, or enter the password interactively. Rexec also doesn't have the functionality where it invokes rlogin if you omit the command...the command is mandatory. ==Why?== No idea. Yes, it's odd that it wasn't all made as a single client binary. There were also different daemons on the server side...rexecd, rshd, rlogind. Also fun, there was often another binary called rsh that had nothing to do with this rsh or remote logins. It was a restricted login shell so that you could have limited rights users.