Maybe this will save you some headaches – if you’re tailing your cron log (tail -f /var/log/cron) and find a bunch of “account expired” records and you know that specific account is not expired, this might help. Try suspending and unsuspending the account. Still no go? This is a rare and very odd issue we ran into, but you may want to check (especially if you’re receiving these errors after repartitioning hard drive space) the crond file itself in /etc/pam.d. In this case it was blanked-out after repartitioning some drive space. If it is blanked out, it will revert to /etc/pam.d/other – which be default, in most cases, is deny. A quick and easy fix is to copy the entires in SSHD – save and restart crond.
Category Archives: Linux
Ruby on Rails – Tutorial 1 – Creating a Rails Project
I heard about Rails back when I was a programmer at BlueHost / Hostmonster since they are one of the “preferred” web hosting companies for Ruby on Rails type applications. There weren’t very many clients who used it, but when questions came in about it, I always seemed to be approached with them. I guess tech support people think that if you are generally willing to help them out and you know a programming language, you know them all. Well, I eventually got sick of saying I don’t know and got some basic knowledge going of Ruby on Rails, and was pleasantly surprised!
Continue reading
Perl on Linux – Greedy Regular Expressions and the Question Marks that Tame Them
In 1986, Larry Wall invented a scripting language to solve the problems of generating reports for system administrators on unix. He called it the Practical Extraction and Reporting Language since that was its function. And it does do that. In a Unix based OS where everything is output in text, Perl has dominated somewhat because it so easy to use but mostly because of its powerful and easily used regular expression capabilities.
Continue reading
Perl on Linux – Formatting Text and Reports
Surely one of the most annoying things about working in a non-gui environment is convenient formatting. We have all had output that was off due to tabs or new lines or variables that overran their boundaries in the output area, etc. Provisioning for such things can be tedious, time consuming, and highly annoying. Luckily for us, perl provides a text formatting feature that is built in and fairly easy to use.
Continue reading
Perl on Linux – Bitwise Manipulations
Today’s attention is directed at one of the less well known and certainly one of the least understood and used areas of perl. Although direct manipulation of bits is the only thing that a computer really does, programmatic manipulation thereof has been abstracted out for all but the tasks that can only be solved by its use. Still, there are situations and times when it becomes necessary and proper for one bit to dissolve the logical bonds which hold them to the byte and to assume, amongst the operators and variables of the language, an equal station.
Continue reading
Perl on Linux – Anonymous Hashes, Hash References, and Passing Them to Subroutines.
There comes a time in every perl programmers life when they have to master the hash. Anyone who has programmed in Perl for very long has run into problems such as subroutine arguments getting confusing, lagging programs due to hash tables being copied over and over, and searched for a simpler way to maintain and access data. All this and more can be achieved by the simple use of anonymous hash tables and the passing of hash table references to subroutines for processing.
Continue reading
Mom, Apple Pie, and Linux
Having purchased an Asus 701 (4G) netbook a couple of months ago, I was very surprised to learn this week that novice PC users, like students and housewives, tend to buy the Linux version of the Eee PC701. My choice of the Eee PC701 was dictated by the fact it came with Linux pre-installed, my personal preferance for any computer, but to see the general public warming up, and actually prefering this hottest selling device in the PC market with Linux was refreshing. Weighing in well under 2lbs, and with built in wifi and webcam, these little machines are perfect for email, chat, web browsing, and music. If you’d like a more advanced experiance, the EeeUser site is filled with tips and tricks to get your mini laptop doing nearly anything you could imagine, and a few things you never thought of.
Perl on Linux – Making a Daemon
One if the nice advantages to linux is the ability to create daemons relatively quickly and get them to do your brute and routine work for you. For this example, I am going to use perl to create the daemon, since perl is the glue that holds the bricks of linux together. Its regex functionality combined with fast and easy syntax makes it almost too easy to use for quick and dirty programming in the text based realm of linux. So without further adieu, the daemon:
Continue reading
Partition madness!
So, you’ve found out the hard way that your ESP wasn’t quite correct when setting up those Linux partitions? Your root directory is almost full, while your home directory is almost empty (or vice-versa)? Thinking about reinstalling that machine? Not so fast! There are tools available to re-allocate partition space – GParted being my favorite. GParted is a free, open source tool to re-distribute disc space to new or existing partitions. You can get a bootable “live cd” here. Simply boot your server, or machine, off this disc and follow the basic setup instructions – the defaults are normally fine. Once GParted starts, you can remove allocated disc space from partitions that have too much space (by using the ‘move’ option) and give them to partitions that don’t have enough. It’s a very simple and easy to use interface. Once you remove some disc space from a partition, apply it, then select the partition you want the disc space to go to and add it there, then apply again. Reboot and you’re done. Depending on the size, type, etc of hard discs you’re using and how much space you’re moving around, it could take quite a while to complete. All in all it’s a very painless and easy way to reallocate partition space.
Run what you want
Would you like to try out Linux, but haven’t a clue how to create a dual boot system? VirtualBox allows you to do just that. This is a software based virtualization platform that runs in Windows, Linux, Mac OS X, and Solaris that supports guests (virtual machines) of the same. Now you can easily roll out a Windows install on your Mac or Linux PC, or any other combination. As seen here, this is one of the coolest Linux demonstration videos I’ve had the chance to view, you’ll notice a Windows XP system running in the opposing desktop view in full screen even. The desktop effects you see are Compiz which I will discuss in a later post.