process

A lot of times when I'm asked to debug a Unix, Linux, or Mac OS X system, I'll hear a complaint like "The network seems slow", or just "It seems slow", followed by the usual "What is it doing?"

I actually think that last question is a wonderful one: What is this computer doing?

You can see a lot of information about Unix processes using the ps command or the top utility, but it seems like many system administrators don't know how to find networking information, at least not without a network sniffer.

Unix/Linux shell script FAQ: How do I write a Unix or Linux shell script where I "do something" for every line in a text file?

Solution: An easy way to process every line in a text file is to use a Unix/Linux while loop in combination with the Linux cat command, like this:

I've been thinking about rewriting my old tutorial on how to execute system processes from a Java application for a while now (How to run system commands from Java applications), but it's a topic that quickly becomes complicated if you want to do it right, so I kept postponing it until I could give it some quality time in a real-world project.

Java Swing drag and drop FAQ: How do I get Java/Swing image drag and drop working on Mac OS X?

I've been working on several new Swing applications for Mac OS X recently, and most of these applications include features like image processing, copy and paste clipboard interaction, and in today's example, dealing with drag and drop events on the Mac.

Many times on Unix and Linux systems you need a Perl script that can open a plain text file, and essentially treat that file as a database. Typically these files have variable-length fields and records, and the fields in each record are delimited by some special character, usually a ":" or "|" character. When processing these files, you can use the Perl split function, which I'll demonstrate in two short programs here.