Best of Technical Support
I have taken over a Linux system for a company. The company uses the box as an Internet server. The problem is that the person I have taken over for left without providing the root password for the box. Is there any way I can find the password, or any way I can recreate it without knowing the original password? —Rusty Mays, email@example.com
When you get the LILO prompt, press the tab key. Find which kernel name is first (probably “linux”) and type
Once you get a prompt, do the following:
mount -wno remount / /bin/vi /etc/passwdThe old trick was to remove the password field (anything between the 1st and the 2nd colon), but some distributions (notably Red Hat) have a bug (or feature, depending on how you look at it) where it won't let you log in as root if there is no password, and also the password command will not work if the password field is blank. The passwd command should work and let you enter a new password even if you don't know the old one (and leave it in place). If that fails, another option is to replace the encrypted password with a known encrypted one, like yours. —Marc Merlin, firstname.lastname@example.org
The passwords used in UNIX/Linux are usually hard to crack, so the best thing to do is to boot from a Linux boot floppy, then edit the password file. Boot from a set of Linux boot floppies, either for an installation or one of the “Linux on a floppy” installations from http://www.toms.net/rb/. After booting from the floppy, mount the hard disc, then make a copy of the password file, just in case (either /etc/passwd or /etc/shadow), then edit the password file (with vi, pico, etc., or use sed and/or cut) to remove the password for root. Finally, unmount the hard disk and reboot, then log in as root and set the root password immediately. It's probably a good idea to check for other accounts with a UID of 0, and accounts you do not recognize. —Keith Trollope, kt57707@GlaxoWellcome.co.uk
My machine at home has a sis6215 chip, and Red Hat 6.0 doesn't have a driver for it. Probably because of this, when Gnome runs, the screen is zoomed and everything is huge. The default resolution is some 320x200. I tried to configure custom settings through Xconfigurator and also X11Config, but the resolution didn't change. Where am I stuck? Is there some problem with my monitor settings? —Pankaj Ratan Lal, email@example.com
According to www.xfree86.org/3.3.6/SiS2.html#2, your chip isn't supported by XFree86. You can still try XFree86 3.3.6, but there aren't many chances it will work. If your chip is VESA 2-compliant, you have another option: use the VesaFB frame buffer, available at www.xfree86.org/FAQ/#FBDev. --Marc Merlin, firstname.lastname@example.org
When I try to set up my modem and use the query modem function, I get a “modem busy” response. This also happens if I use dialup. I use COM3 for my modem, so I set Linux to tty2. I think this is correct. Is it conflicting with Windows? Any suggestions? —Don Hoornaert, email@example.com
Even though many things could be happening (misconfigured port settings, broken modem, misconfigured software, etc.), make sure you have all settings correct and try connecting directly to the modem with cu -l /dev/ttyofyourmodem. The “ttyofyourmodem” depends on which COM port you use; it could be ttyS0, ttyS1, ttyS2 or ttyS3 for COM1, COM2, COM3 or COM4, respectively. If you succeed in connecting to the modem this way and get an OK in response to an AT command, then you are okay. If you bought your computer with Windows pre-installed, it is probable that you have what is called a Winmodem, which is a crippled kind of modem for Windows only. If that is the case, you had better buy a modem that works with Linux. I have bought many 3COM USRobotics “Python” internal modem cards that provide 56K V.90 data/fax/voice services to my Linux servers with excellent results. Check this excellent web page for modem compatibilities: www.o2.net/~gromitkc/winmodem.html. Check the entire modem list table. There are some people trying to make Winmodems work with Linux, but to play safe, buy a new Linux-compatible one. —Felipe E. Barousse, firstname.lastname@example.org
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
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