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14. Solutions to Common Problems

Q: How Do I Remove (or Change) the Colors in the ls Display?
Q: Why Won't a Program Work in the Current Directory?
Q: How Do I Find Out If a Notebook Runs Linux?
Q: Can Can I Resume an Interrupted Download?

Q: How Do I Remove (or Change) the Colors in the ls Display?

A: If ls is displaying in color and you haven't told it to, you probably have an alias configured for it. Some distributions ship this way by default.

The shell command, unalias ls, should completely unset the configuration that some distributions provide as standard.

To permanently make this change, check your initialization script, .bashrc.

A: To change the colors, rather than removing them, refer to the ls man page (man ls).

Q: Why Won't a Program Work in the Current Directory?

A: Because the current directory (i.e., .) is not in the search path, for security reasons, as well as to insure that the correct program versions are used. If an intruder is able to write a file to a world-writable directory, like /tmp, presumably he or she would be able to execute it if the directory were in the search path. The solution to this is to include the directory in the command; e.g., ./myprog, instead of myprog. Or add the current directory to your PATH environment variable; e.g., export PATH=".:"$PATH using bash, although this is discouraged for the reasons mentioned above.

Q: How Do I Find Out If a Notebook Runs Linux?

A: There's no fixed answer to this question, because notebook hardware is constantly updated, and getting the X display, sound, PCMCIA, modem, and so forth, working, can take a good deal of effort.

Most notebooks currently on the market, for example, use "Winmodems," which often do not work with Linux because of their proprietary hardware interfaces. Even notebooks which are certified as "Linux compatible," may not be completely compatible.

Information about installing Winmodems in general is contained in the Winmodems-and-Linux-HOWTO. Refer to Where Is the Documentation?.

You can find the most current information, or ask other users about their notebook experiences, on the linux-laptop mailing list, which is hosted by the vger.redhat.com server. Refer to What Mailing Lists Are There?.

A mailing list for Linux on IBM Thinkpads has its home page at http://www.topica.com/lists/linux-thinkpad/.

Another Thinkpad mailing list is hosted by http://www.bm-soft.com/. Send email with the word help in the body of the message to majordomo@www.bm-soft.com.

There is a Web page about Linux on IBM Thinkpads at http://peipa.essex.ac.uk/tp-linux/.

The Linux Laptop home page is at http://www.cs.utexas.edu/users/kharker/linux-laptop/.

For information about interfacing peripherals like Zip and CD-ROM drives through parallel ports, refer to the Linux Parallel Port Home Page, at http://www.torque.net/linux-pp.html.

If you need the latest version of the PCMCIA Card Services package, it is (or was) located at ftp://cb-iris.stanford.edu/pub/pcmcia/, but that host no longer seems to be available. Recent distributions are on ftp://metalab.unc.edu/pub/Linux/kernel/pcmcia/. You will also need to have the kernel source code installed as well. Be sure to read the PCMCIA-HOWTO, which is included in the distribution.

Q: Can Can I Resume an Interrupted Download?

A: You can use the reget command of the standard ftp client program after reconnecting to pick up where you left off.

Clients like ncftp support resumed FTP downloads, and wget supports resumed FTP and HTTP downloads.