Learning Unix for Mac OS X Tiger

Chapter 4. File Management

The previous chapter introduced the Unix filesystem, including an extensive discussion of the directory structure, the ls command for seeing what files are on your system, and how to move around using cd and pwd. This chapter focuses on Unix filenaming schemes—which aren’t the same as names you’d see in the Finder, as you’ll see—and how to view, edit, rename, copy, and move files.

File and Directory Names

As Chapter 3 explained, both files and directories are identified by their names. A directory is really just a special kind of file, so the rules for naming directories are the same as the rules for naming files.

Filenames may contain any character except /, which is reserved as the separator between files and directories in a pathname. Filenames are usually made of upper- and lowercase letters, numbers, dots (.), and underscores (_). Other characters (including spaces) are legal in a filename, but they can be hard to use because the shell gives them special meanings or otherwise forces you to constantly be changing how you work with these filenames on the command line.

Spaces are a standard part of Macintosh file and folder names, so while I recommend using only letters, numbers, dots, and underscores for filenames, the reality is that you have to work with spaces in file and directory names, because that’s what Mac people do. Rather than naming a file myFile.txt as a Unix person would, most Mac folks are used to adding spaces to filenames, such as my file.txt ...