removing speakup from memory?
oyvind.lode at gmail.com
Sun Jan 25 01:04:56 UTC 2015
Linux and all UNIX-like systems is multi user by default.
The system creates only UIDs that are needed by the system and no
security risk at all.
On a standard installation only your own UID is created and optionally
one for root and then all system users of which are set to /bin/nologin
or something similar.
All these UIDs is required for the system to run properly.
This is how UNIX is designed.
Examples of system UIDs are: bin, daemon etc etc.
To shutdown a linux box 'shutdown -h now' is the correct way.
That said I never shutdown a Linux box because it's designed to be
running 24/7 smile.
On 25/01/2015 01:36, Karen Lewellen wrote:
> why would the system create elements tied to those not actually using
> the system?
> Forgive my lack of information here, but would that not be a security risk?
> If they were not created by me, who would create them?
> I have no means for typing that command, but I am curious about the
> On Sat, 24 Jan 2015, John G. Heim wrote:
>> Multi-user just means that each process is owned by a user. Some
>> user ID is tied to each process. Most of the processes are owned by
>> users you probably didn't create directly. Examine the /etc/passwd
>> file to see all the users on your system.
>> On 01/24/2015 01:36 PM, Karen Lewellen wrote:
>>> Why would I have a multi user system?
>>> Oh wait I might know the answer to this one.
>>> no. this box was built for me, I have an admin password, and I am the
>>> only user. Something I have done once from the computer itself. No
>>> this time, I have no idea yet if the debian configuration on the
>>> even supports dsl.
>>> I will be turning it on to find out.
>>> I will want to turn it off again when I am through, so thanks for all
>>> the prospects.
>>> While Halt seems like the most fun, better to just try shutdown -h.
>>> On Sat, 24 Jan 2015, Tim Chase wrote:
>>> > On January 24, 2015, Karen Lewellen wrote:
>>> > > what is the keystroke for leaving Linux basically to shut down the
>>> > > computer?
>>> > > Unlike DOS, i understand you cannot just turn off the machine.
>>> > > Depending on how new the computer is, you can usually just hit the
>>> > power button to initiate a shutdown (as opposed to holding it in for
>>> > 3-5 seconds which does a hard power-off). The press (rather than
>>> > press-and-hold) sends a shutdown signal to the operating system.
>>> > > If you want to initiate it from the command-line or over SSH,
>>> you can
>>> > usually use one of "halt", "reboot", or "shutdown". You might have
>>> > to prefix it with "sudo" because on a multi-user system, it would be
>>> > rude to allow any old user to reboot it out from under other users.
>>> > I usually use "halt" to power down the machine, and "reboot" to,
>>> > well, reboot (that's rare). The "shutdown" command allows for
>>> > additional options like sending messages to users that are logged in,
>>> > deferring the shutdown for a period of time, etc.
>>> > > So those are the graceful ways to shut down.
>>> > > That said, if you're running a modern vintage of Linux, it
>>> should be
>>> > fairly robust to handling abrupt power-offs. Mostly it boils down to
>>> > things that your software thinks has been written to the drive but
>>> > hasn't actually made it to the drive. If you use a journaling
>>> > file-system (unless you're running a REALLY old version of Linux or
>>> > you intentionally chose EXT2 or a FAT partition type on installation,
>>> > you've likely have a journaling file-system since it's been the
>>> > default for years). Also, if you have external drives like a USB
>>> > drive, you'd want to make sure that either it's set to write
>>> > synchronously or that you properly unmount it since it's usually a
>>> > FAT file-system which can lose data.
>>> > > And if you're booting off a live CD, doing all your work on the
>>> > internet, and not actually saving anything locally? Feel free to
>>> > unceremoniously rip the cord from the wall since there's nothing that
>>> > won't be restored on a fresh boot. Though I still usually just do a
>>> > regular shutdown out of habit. (grins)
>>> > > -tim
>>> > > > > > >
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