$ crontab < /tmp/newcrontab
To see the current crontab configuration, use the -l option:
$ crontab -l
# Backup ~chris/oreilly/ to bluesky:~chris/backup/ as a tar archive
30 0,12 * * * /usr/local/bin/bluesky-backup-oreilly
# Update the local rawhide repository
0 5 * * * /usr/local/bin/rawhide-rsync
Putting these features together, you can create a simple script to edit a crontab configuration:
#!/bin/bash
# addtmpclean :: add a crontab entry to clean ~/tmp daily
(crontab -l ; echo "30 4 * * * rm -f ~/tmp/*")|crontab
6.4.4. Where Can I Learn More?
The manpages for cron , crontab(1), crontab(5), anacron, and anacrontab
Chapter 7. Network Services
Fedora, like most Linux and Unix systems, makes no distinction between server and client systems. In fact, many Fedora systems participate in both roles, both serving and consuming information.
It should come as no surprise, then, that Fedora Core ships with a full complement of software for serving everything from web pages and email to files and printer connections. These server packages are based on open standards and interoperate with other platforms, so you can use a Fedora system to serve Windows, Mac, Linux, or Unix clients.
Most Fedora servers are extensively configurable. Configuration information is stored in text files, but the format of the text files varies, and the information in those files goes by different names directives , statements , parameters , or options depending on the program. Red Hat has developed convenient graphical configuration tools for most of the server configuration files.
Services are programs that constantly run in the background. Services can start automatically when the system starts, but not all services are configured this way by default (see Lab 4.6, "Managing and Configuring Services").
It also might be necessary to adjust your firewall or SELinux configuration to use the services discussed in this chapter (see Chapter 8 for more information).
7.1. Configuring Samba to Share Files with Windows Systems
Fedora can be configured to use Samba to serve files and printers to a wide range of Windows systems using Microsoft-compatible protocols.
Samba can be configured to work with a wide range of Windows versions and to serve resources in many different ways. This lab is focused on sharing files and printers with Windows XP systems in a small workgroup, which is a common scenario in home and small-business networks.
7.1.1. How Do I Do That?
To configure Samba, select the menu option System→Administration→Server Settings→Samba, which will open the window shown in Figure 7-1.
Figure 7-1. Samba configuration window
Click Preferences→Server Settings to open the small window shown at bottom right in Figure 7-1. Enter your local Windows workgroup name into the Workgroup field and click OK. The Sambaserver will be started automatically.
See Lab 4.7, "Managing Users and Groups," to create Fedora accounts for your users before enabling Samba access.
Next, select Preferences→Samba Users to bring up the user configuration dialog box shown in Figure 7-2. Click Add User, select an existing Linux user, enter a Windows username (which may be the same as the Linux username), and enter the Samba password of your choice twice. Click OK when you're done.
Figure 7-2. Samba user configuration
If you are using a firewall or have SELinux enforcing turned on, you will need to adjust your security settings to permit remote systems to access the Samba server (see Lab 8.2, "Using SELinux").
Your system will now be visible to local Windows computers; for example, on an XP system, click My Network Places and then "View workgroup computers," and your Fedora system will appear as an icon with the hostname that you have assigned to it, as shown in Figure 7-3 . Click on the computer icon to see the folders being shared by the Fedora system (after you enter your Samba user ID and password to authenticate).
Figure 7-3. Windows XP workgroup display showing Samba shares from a Fedora system
The folder labeled homes contains the home directory of the authenticated Samba user, and the Printers and Faxes folder will contain all of the printers configured on the Fedora system.
Although the Samba configuration tool starts the Samba system, you'll need to enable the Samba service if you want Samba to start every time you boot your systemsee Lab 4.6, "Managing and Configuring Services."
7.1.1.1. Adding additional Samba shares
To share an additional directory, start the Samba configuration tool (System→Administration→Server Settings→Samba) and click the Add button. The window shown in Figure 7-4 will appear.
Figure 7-4. Adding a Samba share
Under the Basic tab, enter the directory name, the name visible to the Windows systems (i.e., the share name), and a description of what is in the shared directory. Use the checkboxes to configure whether the directory is writable by Windows users, and whether it is visible when the Windows users are browsing using a tool such as Windows Explorer.
Under the Access tab, you can choose to make the directory available to all users, or you can go through the list of Samba users and select the specific ones you want to grant access to it. Click OK when you are done.
In order for a remote user to access a shared directory through Samba, that directory must have the appropriate permissions and SELinux context.
7.1.1.2. Accessing Fedora printers from a Windows system
Fedora's default Samba configuration will make all printers available to Windows users. To use a shared Samba printer in Windows XP, follow these instructions.
Although you can access Fedora printers through Samba printer sharing, it's often faster and easier to access those printers directly through CUPS printer sharing, regardless of the operating system in use.
1. Go to Printers and Faxes and then click "Add a Printer." The Add Printer Wizard will appear. Click Next to get past the introductory message, then select "A network printer, or a printer attached to another computer" for the printer type, and then click Next. Select "Browse for a Printer," and then click Next to see a list of computers on the local Windows network. Double-click on the name of the Fedora system, which will reveal the names of the printers on that system, as shown in Figure 7-5 ; double-click on the desired printer.