When I used to work on a Linux system, there was a utility we had that would let me take screen captures every 30 seconds while my computer was otherwise unattended, as a way to see if anyone else was using it or not. I liked it. Now I'd like to do the same on my Mac system. Possible?

I'm confused: on my Mac when I go to install new software sometimes I just drag and drop it and everything's fine, but other times I get "item in use" errors and have to reboot before I can install the new app. What's up with that?

If you're running an online business like I am, there are times when you need to connect and log in to the server to tweak or check things. It can't be helped and while the Cpanel solution and related are often splendid, sometimes I just like to get bits all over my hands as I "go old school" on my server and use a command line.

In those instances there's a nice solution on the Mac called "Terminal", included with Mac OS X, and there's a rudimentary terminal window app for Windows too, but once you move onto mobile devices of any nature, nothing's available.

That's why I was so interested in iSSH [iTunes link], a low-cost iPad application that lets me connect directly to my Web server via a secure, encrypted connection (SSH = secure shell, it's the secure alternative to "telnet') from my iPad and, in case of a crisis, even my iPhone.

I have a Virtual Private Server or a dedicated server running Linux, but I'm not sure which version of Linux (Fedora, CentOS, Debian, etc.) the server is running. How do I find out?

I have Mac OS X 10.5.8. When I try to change my unix shell prompt by putting the line:

  export PS1='mac> '

into my .bash_profile, the prompt is changed but the cursor is in the first column (over the "m" of my prompt) and any typing overwrites the prompt.

I'm trying to write a shell script that will accept a street address and output the latitude and longitude of that address, for geocache purposes. How can I do that?

I just bought a slick ASUS Eee PC netbook, model 1000HA, and want to configure it to work with both Microsoft Windows XP, which is already installed, and Ubuntu or some other flavor of Linux. How can I do that without having to reinstall WinXP?

I seem to recall a long time ago that when you installed Mac OS X you also got a bunch of cool Unix command line developer tools, including a C compiler, debugging tools and much more. I'm taking a C programming class at the local community college and would like to install these tools, but have no idea where they are any more. Help?

Please, gimme a advice how to correctly use loop "for i in `seq 1 10`" for Mac OS X, echo $SHELL->/bin/bash, because when I write simple strip: for i in `seq 1 10`;do echo $i;done it outputs -bash: seq: command not found.

On page 329 (Hour 16) of your book Teach Yourself Unix in 24 Hours is the example:

Are you able to quickly explain what the line test $value < $(echo $string | wc -c) is actually trying to do? I don’t quite understand the $(…) part … and is the < performing a ‘redirection for input’ or is it meant to be ‘less than’?

I have read about 15 chapters of your book (Teach Yourself UNIX in 24 Hours) so far. We are using vi. On the PS1 command, how do I see what is in it so I can add to it and not change what is already there? We are using bash. What I see now is: ctdaywbsdv:/u/gwilki$

When I enter ‘echo $PS1’ I get: $ \[\e[0m\]

How do I keep the above and add the histcmd option? What does the \e and 0m\ mean? What do the [] the square brackets mean? I can’t find a man page for PS1. How do I find the rest of the options for this PS1?

I just finished Learning Unix for Mac OS X Tiger, and think it is an excellent little resource. I'm recently out of school, a school where we weren't taught anything about Unix, just enough to get by. I started work with the data converter team at Agilent labs, and have been able to glean quite a bit off of them (considering many of them were either directly or indirectly responsible for writing many of them commands in common use today). Thus, I'm often embarrassed to ask them questions about exactly some of the stuff you cover in the book.

Okay, now for the question: at work, they have the terminal set up such that the command line works like vi. That is, if I want to search my command history, I simply change mode via escape, type /pattern_to_be_searched, it finds the command, and then I can use other vi commands to change the command a little bit, and then execute it via the shell. How do I set this up in OS X?

I have a script that does an ftp from a SCO UNIX server to windows server to get files from the windows server. The script is set in the cron to run every xx minutes. Sometimes the script will hang and leave a process running. This can bog down the UNIX server. I want to be able to do two things. 1. I want to make sure that the script doesn't hang - so it should terminate after xx minutes (the files are very small that it is getting). And 2. I want the script to test to make sure that it is not already running, before starting again. THANKS

I'm a bit baffled. I'm trying to compare string variables in a shell script to figure out if one value is lexically less (that is, would appear earlier in the dictionary) than another, but it doesn't seem to work at all? Help!

I need to run a Unix application if a different application is running, from within a shell script. How do I do this?