“UbuntuHelp:SwitchingToUbuntu/FromLinux”的版本间的差异

2008年10月20日 (一) 00:43的版本

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https://help.ubuntu.com/community/SwitchingToUbuntu/FromLinux

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1. title Switching to Ubuntu from other Linux/UNIX distributions

Many people who use Unix-like Operating Systems make the switch to Ubuntu everyday and even more are considering it. This page shows the Ubuntu equivalents of many traditional Unix applications,and tasks. There are also specialized guides for users of Red Hat/Fedora and Mac OS X.

Performing Administrative Tasks

Ubuntu handles the root user a little differently to most other Linux distributions in that it has the root account disabled by default. Instead Ubuntu uses the "sudo" program to allow users in the 'admin' group to run particular commands as root. Graphical config tools also prompt for your password using a similar system. This has many advantages:

• You can't do anything really bad to your system unless you use sudo each time.
• You don't have to remember a root password - sudo only needs your own account's password.
• sudo remembers for a limited time that you used your password, so you won't have to enter your password every time you use it.

At first only the user you create during installation will have access to sudo. To allow additional users to use sudo, add them to the admin group.

Using Sudo

To run a command with root privileges, simply open a terminal and type:

sudo <command>

Replace <command> with the command you wish to use. Sudo will then ask for your normal user password; enter it and press return to run the command. Sudo also has a graphical mode, if you try to run a program from the menu system (such as Synaptic) that requires root privileges a dialog box will appear asking you to enter your normal user password. Enter your user password and click Continue or press the enter button on your keyboard. To run a proper root shell you can do the following:

sudo -i

This will ask for your normal user password, enter it and you will be at the root prompt.

Packaging

For Debian Users

Packages in Ubuntu can be handled the same way as in Debian using apt-get/synaptic/aptitude from the command line, or using the Synaptic or Gnome-app-install graphical installers. Most of the Debian pool is available to Ubuntu users through the extra Universe and Multiverse repositories, which are not enabled on a default install (see AddingRepositoriesHowto to enable them). Optionally you can open /etc/apt/sources.list with your favorite editor and uncomment the relevant lines to enable the extra repositories. Every six months a snapshot of Debian Unstable is made and Ubuntu is created from that. That said, installing packages made for Debian on your Ubuntu system can often cause problems due to the minor differences and tweaking the Ubuntu developers need to do to make Ubuntu stable - use Ubuntu's Universe and Multiverse repositories instead for you extra software needs. See Installing Software for information on installing packages.

Command Line configuration (aliases and inputrc)

This section is written for Mandrake/Mandriva users, but probably applies generally.

Useful Shell aliases

Mandriva defines the following aliases (in /etc/profile.d/alias.sh), which make the shell faster to use. They could also go in your .bashrc

The following make cp,rm, and mv interactive by default, so you don't overwrite a file by mistake. Most people think this is useful, but some think it makes one careless, as one might come to rely upon the implicit -i, on some other system which doesn't have it.

Note that these aliases do not work when running a command as root using sudo. One workaround for this is to add alias sudo="sudo " as an additional alias (note the space behind the sudo, inside the quotes); which will make the first word after 'sudo' be substituted if an alias exists.<<FootNote(Source: https://lists.ubuntu.com/archives/ubuntu-users/2005-June/039274.html)>>

Tab Completion Enhancements

Mandriva defines the following in /etc/inputrc (it could also go in ~/.inputrc), which makes tab-completion much more pleasant. In Ubuntu/Debian/RedHat, when tab-completion has several possible alternatives, it simply beeps. In Mandriva, it prints the list of options and then repeats the prompt where you were. Furthermore, the system beep is now rarer, and when it does beep, it's meaningful, rather than annoying.

set show-all-if-ambiguous on

Music, Movies, DVD Playback and Java

Getting file formats restricted by patents or copyright such as movies and music to play on your Ubuntu system is simple (although not as simple as it could be). See RestrictedFormats. Java is simple too.

Services, Chkconfig and Initscripts

Users of Red Hat and Mandriva will be used to configuring which services run by using the chkconfig command, for example, chkconfig sshd on. In Ubuntu, chkconfig is not available, however there is an alternative, sysv-rc-conf (which is not installed by default). Also, to stop/start services, it's necessary to invoke the init.d script directly: /etc/init.d/ssh start, rather than service sshd start. If you want to have the 'service' syntax back, add this to root's .bashrc:

function service (){ /etc/init.d/$@ ;}  

Ubuntu runs in runlevel 3 by default, whereas RH/Mdv use runlevel 5 for graphics, and 3 for console. Also, Ubuntu has an extra rcX.d directory, /etc/rcS.d, which is run at boot-up; udev and similar are started here. There are some helpful READMEs in the /etc/rcX.d directories.

Environment Variables

See Environment Variables for a full guide to the use of environment variables in Ubuntu.

Documentation

There are a few good resources you can turn to if you need further help with Ubuntu, these include:

• http://help.ubuntu.com - The main source of Ubuntu documentation
• Press System -> Help and Support to access the system documentation
• Man and info pages on your system
• Forums, Mailing Lists and IRC (irc.freenode.net - #ubuntu)