Mac OS X: The Missing Manual, Panther Edition

Where to Go from Here

This crash course in Unix should give you a first helping of guidance—enough to perform some genuinely useful tasks in Mac OS X, and to acquire a feeling for how Unix commands work.

There’s a lot more to learn, however. As you peruse beginner-level Unix books and Web sites (see Appendix E), for example, you’ll gradually become familiar with a variety of important terms and tools.

Aliases

Don’t be confused: Aliases in Unix have nothing to do with traditional Macintosh icon aliases. Instead, Unix aliases are more like text macros, in that they’re longish commands that you can trigger by typing a much shorter abbreviation.

POWER USERS’ CLINICSecrets of Virtual Memory

The top command’s table offers a fascinating look at the way Mac OS X manages memory. In the “VM” section, for example, you’ll see current statistics for pageins and pageouts—that is, how many times the virtual-memory system has had to “set down” software code for a moment as it juggles your open programs in actual memory. (These numbers are pointed out in Figure 16-3.)

The pageins and pageouts statistics are composed of two different numbers, like this: 45451(0) pageins, 42946(0) pageouts. The big number tells you how many times your Mac has had to shuffle data in and out of memory since the Mac started up. The number in parentheses indicates how much of this shuffling it’s done within the last second.

This is the number to worry about. If it stays above zero for a while, your Mac is gasping for RAM (as ...