The Elemental Linux Server (ELS) is a niche distribution and is not intended to run on every imaginable hardware configuration. Specifically, it is designed to run on standard x86 PC architecture using SATA or IDE hard drives and CD-ROMs.
ELS will not coexist with other operating systems. It expects to have full control over all hard drives it detects. You cannot configure ELS to dual-boot another OS using the included setup utility.
On the positive side, ELS has very low system requirements. It can easily run on older, discarded hardware, newer "value PCs" or minimally configured virtual machines. Minimum recommended requirements are Pentium II with 128M RAM and a 2G hard disk. Anything exceeding these specs should make a very capable system indeed.
Installation
The most straightforward way to install ELS is from a bootable CD-ROM. Visit the ELS home page, download the latest .iso image and burn it to CD. The instructions in the following sections are centered around CD-ROM based installation.
Note
The default action for the CD-ROM is to boot the operating system on the hard drive after a 30 second delay. You must manually select "Install Elemental Linux Server" from the CD's bootloader menu to access the installer.
Initial install
Upon booting from the ELS CD-ROM you will find yourself at a login prompt. To begin installation, log in as root and type setup to launch the installer script.
When the installation script is finished you will be returned to a shell prompt with a message instructing you to reboot using CTRL-ALT-DELETE. After restart, the system will boot into single-user mode. At this point you can log onto the server console as root and begin configuration.
System configuration
ELS does not have any specialized system administration tool. Everything is done by issuing standard commands at the shell prompt or editing files in the /etc directory. Methods for performing common tasks are detailed below.
Initial configuration
The system is not very useful after the initial installation. If you want to do anything interesting, you'll need to configure the system further. A checklist for getting started is provided below.
Change the root password and set up at least one non-privileged user.
Configure the system time.
Create a swap file.
Create filesystems for additional software and home directories.
Configure IP networking.
Configure system startup.
Install additional software if desired.
Setting up users and passwords
One of the first steps you should take to secure the system is to set the root password and get in the habit of logging in as a non-privileged user.
To set the root password simply issue the passwd command while logged in as root.
Any non-privileged users can be created by using the following procedure:
Use the groupadd command to create a new group for general users if one does not exist already.
Create a new user account with the useradd command using the man page or example below to determine appropriate command-line options.
Set the initial password for the user by issuing the command passwd username.
Example
The following example show the commands you could use to set the root password and then create a non-privileged user named "Joe Smith".
passwd
groupadd -g 500 users
useradd -c "Joe Smith" -g 500 -m -s /usr/bin/bash joe
passwd joe
Notes
You can make your life easier by creating some default values for the useradd command. The command useradd -D shows the current defaults and useradd -D with additional command-line options will set new default values for those options.
To further secure the system, you can use the pwconv and grpconv commands to switch over to shadow password and group database files.
Configuring system time
There are two steps in setting the system time. First, you must set the CMOS clock to Coordinated Universal Time (UTC). Next, you need to set the time zone for your location.
To set the clock, you can use either the hwclock command or your PC's BIOS setup utility. If you choose to use hwclock, it is a two step process.
Set the CMOS clock to Coordinated Universal Time.
Tell the Linux kernel to update its time by reading the CMOS clock.
Here are the steps to set the time zone:
Remove any existing /etc/localtime file.
Browse through the /usr/share/zoneinfo directory and its subdirectories and note the path to the file that most closely matches your geographic location or time zone.
Copy the file found in the previous step to /etc/localtime.
Example
The following example shows how you might set the system time and the time zone if you lived in Chicago, USA.
Occasionally countries make changes to Daylight Saving Time rules. If this happens to you, you'll need to download an updated time zone file from http://www.iana.org/time-zones, extract it to the /usr/share/tzdata directory and recompile the zonefiles with the zic command.
Creating a swap file
If you have a small amount of RAM in your system, you will probably want to create a swap file to avoid running out of memory. Just how big that swap file needs to be depends on a number of factors including how much RAM you have, how much load you intend to put on the system and how much hard drive space is available. Fortunately, file-based swapping is flexible so you don't have to get it exactly right the first time.
Start by configuring a 64M swap file in the /var directory. Here's how to set it up:
Change directory to /var.
Create an empty 64M file called swap using the dd command.
Create a swap filesystem on the file using the mkswap command.
Add the swap file to the /etc/fstab file.
Activate the swap space with the swapon command.
Example
The following example shows the commands used to set up the initial 64M swap file described above.
cd /var
dd if=/dev/zero of=swap bs=1M count=64
mkswap swap
echo "/var/swap swap swap defaults 0 0" >> /etc/fstab
swapon -a
Note
You can check your swap usage with the free command. If you find your system's swap needs changing over time, you can always add or remove swap files as needed. Just be sure that if you create one, it's on a filesystem with plenty of available space.
Creating additional filesystems
The base installation of ELS does not set aside any space for additional programs or user data. You will need to carve out more space for these things depending on how you want to use your server. Here is how to do it.
Create a new partition using fdisk.
If you use mirroring, create a second partition of equal size and mirror the two using mdadm.
Create a filesystem using the mke2fs command.
Add the new filesystem to /etc/fstab.
Mount the filesystem.
Depending on the available hard drive space you'll want to create a filesystem for /opt that is about 600M or more. All ELS add-on software is configured to install in /opt and 600M should give just enough room if you install everything on the CD-ROM. Any remaining space on the hard drive can be given to other filesystems like /usr/local or /home.
Example
The following examples shows how to create a filesystem for /opt on the system. Two examples are shown. The first is for a system that uses only a single disk, the second is for a system with two disks in a mirrored configuration. Choose the one that is most appropriate for your configuration.
After using creating partitions, you may see a message telling you that the device or resource is busy and that the kernel still uses the old table. If you see this message, you should finish partitioning and reboot the system before continuing with mirroring or creating filesystems.
Configuring IP networking
The ELS system comes with kernel modules for a large number of 10/100 and gigabit network cards. Before configuring networking, you must determine the kernel module that supports your hardware. Most modules have a name similar to that of the card or card's chipset.
Steps to enabling IP networking include the following:
Browse the /lib/modules/kernel.version.number/kernel/drivers/net directory to find the appropriate kernel module for your network card.
Edit /etc/modprobe.d/eth.conf and add an alias for netdev-eth0 that refers to your network hardware's kernel module.
Set the hostname in /etc/hostname.
Enter an IP address and mask in /etc/interfaces.
Create an entry in /etc/hosts for the local machine and any other devices on your Local Area Network (LAN).
Set the gateway address in /etc/routes.
Add your DNS server information to /etc/resolv.conf.
Configure any desired firewall rules in /etc/firewall.
Start the networking subsystem using the /etc/init.d/network script.
Each of the network configuration files mentioned above has a man page associated with it to help you with configuration.
Example
The following is an example of editing the configuration files for a typical small network setup using an Intel Pro 1000 network card.
vi /etc/modprobe.d/eth.conf
alias netdev-eth0 e1000
vi /etc/hostname
els.mynetwork.lan
vi /etc/interfaces
eth0 192.168.1.100 netmask 255.255.255.0
vi /etc/hosts
192.168.1.100 els.mynetwork.lan
192.168.1.101 laptop.mynetwork.lan
192.168.1.1 router.mynetwork.lan
vi /etc/routes
default gw 192.168.1.1
vi /etc/resolv.conf
domain mynetwork.lan
nameserver 10.10.10.53
nameserver 10.10.11.53
vi /etc/firewall
-A INPUT -i eth0 -s 192.168.1.0/24 -j ACCEPT
Notes
The example above only highlights some of the necessary changes to the configuration files and is not represent complete files.
The IP addresses and domain names shown are for demonstration purposes only and should be changed to fit your network setup.
Configuring system startup
When ELS is first installed, it is configured to boot into runlevel 1 (single-user mode.) Single-user mode is generally only entered when doing system maintenance and is not used for everyday tasks. After you have finished configuring the system, you will want to change the default runlevel, particularly if you plan to have the system attached to a network. To do this, edit the initdefault entry of /etc/inittab. Choose runlevel 2 for a non-networked machine or runlevel 3 for a machine with a network connection.
Example
The following entry shows the system configured to start in networked mode:
id:3:initdefault:
Congratulations, the basic system configuration is finished. Your changes will take effect on the next reboot.
Additional administrative tasks
This section provides a reference for things that you may need to do after the basic system configuration is finished.
Installing additional pre-packaged software
Add-on packages for ELS are found on the ELS-EXTRA CD-ROM. They are packaged as simple .tar.gz files and are designed to reside in the /opt directory.
The procedure for installing add-on software is outlined below.
Preview the contents of the package with the tar -ztvf command.
Check for available space in the /opt filesystem using df.
Change to the / directory and extract the package with the tar -zxf command.
Create symbolic links to the package's executables in /opt/bin and, if necessary, /opt/sbin and /opt/lib directories.
If needed, create customized configuration files in the /etc/opt directory.
Example
The following simple example shows how you might install the Midnight Commander file manger on your ELS system.
mount /media/cdrom
tar -ztvf /media/cdrom/extra/mc-4.8.1.7.i586.tar.gz
df /opt
cd /
tar -zxf /media/cdrom/extra/mc-4.8.1.7.i586.tar.gz
mkdir /opt/bin
cd /opt/bin
ln -s ../mc-4.8.1.7/bin/* .
Note
More complex examples of installing add-on software may be seen by viewing the documents in the howto directory.
Maintaining info pages
Info pages are different than man pages in that they have a top-level directory that serves as a master table of contents. This file, /usr/share/info/dir needs to be maintained or the info page collection will appear incomplete. If new packages with info pages are installed they will not appear in the table of contents until the directory is updated. Also, if the dir file is missing, typing info at the shell prompt will result in an error.
The command used to add info pages to the dir file is install-info. To create a table of contents that includes all info pages, first delete the existing dir file and then use the command ( cd /usr/src/info ; for INFOFILE in *.info.gz; do install-info $INFOFILE; done )
Configuring network services
Basic network services like telnet, tftp, pop3 and imap are controlled from /etc/inetd.conf and generally do not require any additional configuration. Other network daemons like Apache, Samba and ProFTPd are controlled using scripts in /etc/init.d. These daemons also have configuration files within the /etc/opt directory. See the documentation included with these daemons for more information on how to configure them.
Note
Be sure to configure firewall rules to grant or restrict access to the desired network services.
Controlling what runs at startup and shutdown
The runlevels in ELS are defined as follows:
0 - system shutdown
S - system initialization
1 - single-user mode
2 - multi-user mode, no networking
3 - multi-user mode with networking
4 - not defined
5 - not defined
6 - system reboot
The scripts used during system startup and shutdown are located in the /etc/init.d directory. Each script is named after the service it controls (e.g. exim starts/stops the Exim mail server.) Determining which scripts will run during startup/shutdown is as simple as answering the following questions:
Does the script have its execute bit set? If not, the script is effectively disabled it will never run. You can enable it using the command chmod +x scriptname.
Is there a symbolic link pointing to the script in any of the rcX.d directories? If there is a link in rc3.d, but not in rc2.d, the service will start in runlevel 3, but not in runlevel 2.
Most scripts are pre-configured to run in the appropriate runlevels, however there may be times when you will need to link scripts manually. Creating a link name that begins with the letter 'S' will cause the script to be given a start argument. Conversely, any link name that begins with the letter 'K' will cause the script to be given a stop (kill) argument. Linked scripts are executed in alpha-numerical order. For example, K97local_fs will execute before K99poweroff and K scripts always execute before the S scripts.
Example
Below is an example of how you might set up links to start a fictitious "foo server" in runlevel 3 and stop it in runlevels 0, 1, 2 and 6.
cd /etc/rc3.d
ln -s ../init.d/foo S45foo
cd /etc/rc0.d
ln -s ../init.d/foo K55foo
cd /etc/rc1.d
ln -s ../init.d/foo K55foo
cd /etc/rc2.d
ln -s ../init.d/foo K55foo
cd /etc/rc6.d
ln -s ../init.d/foo K55foo
Note
The scripts in the /etc/init.d directory may also be run manually from a shell prompt. Each of the scripts takes a start or stop argument to respectively start or stop a daemon or process. For example, /etc/init.d/crond stop will manually stop the cron daemon. Some scripts also take a status argument to show the current state of the daemon and a restart argument to stop and start with a single command.
Configuring your ELS system to for specific applications
Chances are good that you'll want to do something interesting with your ELS system. Maybe you'll want to use it as a home file server or run an intranet web site on it. Several "/elemental/howto" documents are provided for these sorts of tasks. More information can be found in the howto directory.
A much more important factor in the social movement than those already mentioned was the ever-increasing influence of women. This probably stood at the lowest point to which it has ever fallen, during the classic age of Greek life and thought. In the history of Thucydides, so far as it forms a connected series of events, four times only during a period of nearly seventy years does a woman cross the scene. In each instance her apparition only lasts for a moment. In three of the four instances she is a queen or a princess, and belongs either to the half-barbarous kingdoms of northern Hellas or to wholly barbarous Thrace. In the one remaining instance208— that of the woman who helps some of the trapped Thebans to make their escape from Plataea—while her deed of mercy will live for ever, her name is for ever lost.319 But no sooner did philosophy abandon physics for ethics and religion than the importance of those subjects to women was perceived, first by Socrates, and after him by Xenophon and Plato. Women are said to have attended Plato’s lectures disguised as men. Women formed part of the circle which gathered round Epicurus in his suburban retreat. Others aspired not only to learn but to teach. Arêtê, the daughter of Aristippus, handed on the Cyrenaic doctrine to her son, the younger Aristippus. Hipparchia, the wife of Crates the Cynic, earned a place among the representatives of his school. But all these were exceptions; some of them belonged to the class of Hetaerae; and philosophy, although it might address itself to them, remained unaffected by their influence. The case was widely different in Rome, where women were far more highly honoured than in Greece;320 and even if the prominent part assigned to them in the legendary history of the city be a proof, among others, of its untrustworthiness, still that such stories should be thought worth inventing and preserving is an indirect proof of the extent to which feminine influence prevailed. With the loss of political liberty, their importance, as always happens at such a conjuncture, was considerably increased. Under a personal government there is far more scope for intrigue than where law is king; and as intriguers women are at least the209 equals of men. Moreover, they profited fully by the levelling tendencies of the age. One great service of the imperial jurisconsults was to remove some of the disabilities under which women formerly suffered. According to the old law, they were placed under male guardianship through their whole life, but this restraint was first reduced to a legal fiction by compelling the guardian to do what they wished, and at last it was entirely abolished. Their powers both of inheritance and bequest were extended; they frequently possessed immense wealth; and their wealth was sometimes expended for purposes of public munificence. Their social freedom seems to have been unlimited, and they formed combinations among themselves which probably served to increase their general influence.321 The old religions of Greece and Italy were essentially oracular. While inculcating the existence of supernatural beings, and prescribing the modes according to which such beings were to be worshipped, they paid most attention to the interpretation of the signs by which either future events in general, or the consequences of particular actions, were supposed to be divinely revealed. Of these intimations, some were given to the whole world, so that he who ran might read, others were reserved for certain favoured localities, and only communicated through the appointed ministers of the god. The Delphic oracle in particular enjoyed an enormous reputation both among Greeks and barbarians for guidance afforded under the latter conditions; and during a considerable period it may even be said to have directed the course of Hellenic civilisation. It was also under this form that supernatural religion suffered most injury from the great intellectual movement which followed the Persian wars. Men who had learned to study the constant sequences of Nature for themselves, and to shape their conduct according to fixed principles of prudence or of justice, either thought it irreverent to trouble the god about questions on which they were competent to form an opinion for themselves, or did not choose to place a well-considered scheme at the mercy of his possibly interested responses. That such a revolution occurred about the middle of the fifth century B.C., seems proved by the great change of tone in reference to this subject which one perceives on passing from Aeschylus to Sophocles. That anyone should question the veracity of an oracle is a supposition which never crosses the mind of the elder dramatist. A knowledge of augury counts among the greatest benefits222 conferred by Prometheus on mankind, and the Titan brings Zeus himself to terms by his acquaintance with the secrets of destiny. Sophocles, on the other hand, evidently has to deal with a sceptical generation, despising prophecies and needing to be warned of the fearful consequences brought about by neglecting their injunctions. The stranger had a pleasant, round face, with eyes that twinkled in spite of the creases around them that showed worry. No wonder he was worried, Sandy thought: having deserted the craft they had foiled in its attempt to get the gems, the man had returned from some short foray to discover his craft replaced by another. “Thanks,” Dick retorted, without smiling. When they reached him, in the dying glow of the flashlight Dick trained on a body lying in a heap, they identified the man who had been warned by his gypsy fortune teller to “look out for a hidden enemy.” He was lying at full length in the mould and leaves. "But that is sport," she answered carelessly. On the retirement of Townshend, Walpole reigned supreme and without a rival in the Cabinet. Henry Pelham was made Secretary at War; Compton Earl of Wilmington Privy Seal. He left foreign affairs chiefly to Stanhope, now Lord Harrington, and to the Duke of Newcastle, impressing on them by all means to avoid quarrels with foreign Powers, and maintain the blessings of peace. With all the faults of Walpole, this was the praise of his political system, which system, on the meeting of Parliament in the spring of 1731, was violently attacked by Wyndham and Pulteney, on the plea that we were making ruinous treaties, and sacrificing British interests, in order to benefit Hanover, the eternal millstone round the neck of England. Pulteney and Bolingbroke carried the same attack into the pages of The Craftsman, but they failed to move Walpole, or to shake his power. The English Government, instead of treating Wilkes with a dignified indifference, was weak enough to show how deeply it was touched by him, dismissed him from his commission of Colonel of the Buckinghamshire Militia, and treated Lord Temple as an abettor of his, by depriving him of the Lord-Lieutenancy of the same county, and striking his name from the list of Privy Councillors, giving the Lord-Lieutenancy to Dashwood, now Lord Le Despencer. "I tell you what I'll do," said the Deacon, after a little consideration. "I feel as if both Si and you kin stand a little more'n you had yesterday. I'll cook two to-day. We'll send a big cupful over to Capt. McGillicuddy. That'll leave us two for to-morrer. After that we'll have to trust to Providence." "Indeed you won't," said the Surgeon decisively. "You'll go straight home, and stay there until you are well. You won't be fit for duty for at least a month yet, if then. If you went out into camp now you would have a relapse, and be dead inside of a week. The country between here and Chattanooga is dotted with the graves of men who have been sent back to the front too soon." "Adone do wud that—though you sound more as if you wur in a black temper wud me than as if you pitied me." "Wot about this gal he's married?" "Don't come any further." "Davy, it 'ud be cruel of us to go and leave him." "Insolent priest!" interrupted De Boteler, "do you dare to justify what you have done? Now, by my faith, if you had with proper humility acknowledged your fault and sued for pardon—pardon you should have had. But now, you leave this castle instantly. I will teach you that De Boteler will yet be master of his own house, and his own vassals. And here I swear (and the baron of Sudley uttered an imprecation) that, for your meddling knavery, no priest or monk shall ever again abide here. If the varlets want to shrieve, they can go to the Abbey; and if they want to hear mass, a priest can come from Winchcombe. But never shall another of your meddling fraternity abide at Sudley while Roland de Boteler is its lord." "My lord," said Edith, in her defence, "this woman has sworn falsely. The medicine I gave was a sovereign remedy, if given as I ordered. Ten drops would have saved the child's life; but the contents of the phial destroyed it. The words I uttered were prayers for the life of the child. My children, and all who know me, can bear witness that I have a custom of asking His blessing upon all I take in hand. I raised my eyes towards heaven, and muttered words; but, my lord, they were words of prayer—and I looked up as I prayed, to the footstool of the Lord. But it is in vain to contend: the malice of the wicked will triumph, and Edith Holgrave, who even in thought never harmed one of God's creatures, must be sacrificed to cover the guilt, or hide the thoughtlessness of another." "Aye, Sir Treasurer, thou hast reason to sink thy head! Thy odious poll-tax has mingled vengeance—nay, blood—with the cry of the bond." HoME古一级毛片免费观看
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