Naming a file in Unix

When you save a paper, spreadsheet, picture or mail message, your work is stored as a file. There are rules for the ways you can name files. You can use letters, numerals, periods and the underscore (_), but do not use other punctuation marks such as question marks, slashes, exclamation points or dollar signs. Unix reserves these and a few other symbols for special system functions.

Unix is also case-sensitive, so you might want to stick to using lowercase letters to cut down on possible confusion and to make file names easier to type. Here are some examples of file names:

biology_homework_3        peter_reply.txt    
testdata                  resume
chem.doc                  my3paper_blake

File names are case-sensitive, which means that a file named "testdata" is not the same as one named "TestData" or one named "TESTDATA." Unix file names can be up to 256 characters in length, but you should use only enough to clearly and easily identify the file and its contents.

Be careful when using a period (dot) in your file name to create an extension, since periods and the extension following often have special meanings in Unix. For example, a file ending in ".c" would indicate to Unix a program written in the C programming language. Underscores often are good characters to use in long files name to separate different parts of the name.

NOTE: If you are a DOS user, you will notice that you are no longer restricted to file names with eight or fewer characters followed by an optional period and three characters. If you want to copy files from your Unity account to your DOS machine without having to rename them, you might want to use the DOS naming conventions, since most DOS file names are acceptable Unix names.

Last modified October 19, 2005 cawalker