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July 2013

Using SCO Unix as a firewall 
- Given the current cost of hardware and the availability of Linux software, why on earth would you want to run a firewall on a production server?
 
Fixing an old SCO Unix 5.0.4 machine   by Anthony Lawrence
- I found myself staring at an ancient Gateway and a screen hung at Enter run level (0-6, s or S)
 
Serial Printers 
- The secret to success with printers on serial ports is understanding that the computer and the printer must agree on baud rate and flow control
 
Printer Problems/Solutions 
- SCO Unix Sys V printing basics - explaining interface scripts, simple printer issues and more. Some of this will apply to CUPS printing.
 
SCO Merge Notes   by Anthony Lawrence
- I did find a customer still using SCO Merge as recently as 2009! They had old Lotus spreadsheets..
 
Another Perl link checker   by Anthony Lawrence
- I'm still trying to write the perfect link checker for my site.
 
How do I find out what IP address a user logged in from?  by Anthony Lawrence
- Obtaining a client IP address on Linux/Unix is not always direct or easy. You may have to dig it out of shell command output.
 
Sendmail on older SCO Unix  by Anthony Lawrence
- I DON'T RECOMMEND running a mailserver on old SCO Unix! That noted, here is a pile of stuff related to Sendmail on SCO Unix.
 
Pass-Through Printing  by Anthony Lawrence
- The idea of transparent printing is that if the terminal sees a special key sequence, it will start sending the data out some other port (parallel or serial) until it sees some sequence that tells it to stop.
 
All about Telnet  by Anthony Lawrence
- A collection of telnet related information and links. Telnet is seldom used today except for network troubleshooting.
 
Overview of Visionfs On SCO Unix  by Anthony Lawrence
- If you find yourelf in the unfortunate position of having to use Visionfs on older SCO, here are some things to know.
 
Learning Perl - why you should even if you'll never use it   by Anthony Lawrence
- That 'you should learn Perl even if you'll never use it' may seem like an odd thing to say: why learn something that you might never use?
 
Computer basics - cut and paste and beyond   by Anthony Lawrence
- There are few things that have surprised me more than finding people who do not know how to copy text from one place to another. If that's you, read on..
 
Computer basics - Right Click your way to Computer Happiness   by Anthony Lawrence
- One thing I really recommend is right-clicking. You can really learn a lot about your computer by exploring the options available with a right-click.
 
SCO Unix Performance Tuning   by Anthony Lawrence
- People who are stuck running legacy SCO Unix systems may find these tips useful.
 
Losing white space IFS  
- The shell doesn't really destroy anything; it's just doing what it should - ignoring repeated white space.
 
View large files without more or less  
- I have a rescue disk that doesn't include "more" or "less" - how can I examine large files?
 
Deleting a lost file name - delete unremoveable files 
- Control characters and a little bad advice about files and file systems confuse this administrator
 
Is your job safe from robotics and computers? Are you sure?  by Anthony Lawrence
- It's becoming very hard to predict what jobs may be available over the next few decades.
 
Passing shell environment variables   by Anthony Lawrence
- Is there any way for a child process to set an environment variable visible to its parent?
 
The best advice I can give for buying a new computer   by Anthony Lawrence
- Everything you really need to know about buying a new computer, from make andf model to how fast and more.
 
Mysterious panics and freezes   by Anthony Lawrence
- Crashes, panics and freezes: all work halts and you can't help being surprised. What just happened?
 
Determine Unix/Linux version and cpu's 
- Usually some variant of uname, often 'uname -a', but all sorts of other possibilies; it depends on the Unix and in some cases even the specific version.
 
How to trouble-shoot "file corruption" 
- If you don't have the space, you have to take running snapshots with fuser or lsof- that may not satisfy a very stubborn vendor who is convinced that *their* programs never screw up.
 
Difference between /dev/sr0 and /dev/scd0 
- Why does the system call the same device by two different names and what is a block device vs, a character device?
 
Wall and write 
- The Unix/Linux "wall" command does that. Login as root, type "wall" <ENTER>, then whatever you want to say (multiple lines are OK), follwed by <ENTER> and then CTRL-D
 
Shebang - What's the point of #!/bin/bash?   by Anthony Lawrence
- Shebang, hashbang, pling - whatever you call it, what's the point? What does it do? Do you need it in shell scripts or not?
 
Why does so much of Unix and Linux have to be hard? 
- Obviously you have REASONS for sharing whatever it is you shared. Sometimes those reasons are completely altruistic, sometimes not
 
Why won't IT staff recommend Macs or Linux? 
- Is the Windows-only wall crumbling? Yes, certainly, but it isn't quite ready to fall down just yet. Windows will die off, but it probably won't be replaced by Unix or Linux.
 
What does 'everything is a file' really mean?   by Anthony Lawrence
- Everything is a file? How ridiculous: is a horse a file? How about a pitcher of beer dumped over the nearest Unix geek's head - is THAT a file?
 
When bad things happen to good computers   by Anthony Lawrence
- Computers are usually very reliable, sometimes running for decades with no attention. On the other hand, sometimes bad things happen..