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When you have a number of files named in series (for example, chap1 to chap12) or filenames with common characters (such as aegis, aeon, and aerie), you can use wildcards to specify many files at once. These special characters are * (asterisk), ? (question mark), and [ ] (square brackets). When used in a file or directory name given as an argument on a command line, the following is true:
The following examples show the use of wildcards. The first command lists all the entries in a directory, and the rest use wildcards to list just some of the entries. The last one is a little tricky; it matches files whose names contain two (or more) a's.
$ ls chap10 chap2 chap5 cold chap1a.old chap3.old chap6 haha chap1b chap4 chap7 oldjunk $ ls chap? chap2 chap5 chap7 chap4 chap6 $ ls chap[5-7] chap5 chap6 chap7 $ ls chap[5-9] chap5 chap6 chap7 $ ls chap?? chap10 chap1b $ ls *old chap1a.old chap3.old cold $ ls *a*a* chap1a.old haha
Wildcards are useful for more than listing files. Most Unix programs accept more than one filename, and you can use wildcards to name multiple files on the command line. For example, the less program displays a file on the screen. Let's say you want to display files chap3.old and chap1a.old. Instead of specifying these files individually, you could enter the command as:
$ less *.old
This is equivalent to "less chap1a.old chap3.old".
Wildcards match directory names, too. You can use them anywhere in a pathname--absolute or relative--though you still need to separate directory levels with slashes (/). For example, let's say you have subdirectories named Jan, Feb, Mar, and so on. Each has a file named summary. You could read all the summary files by typing "less */summary". That's almost equivalent to "less Jan/summary Feb/summary ..." but there's one important difference: the names will be alphabetized, so Apr/summary would be first in the list.
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| 4. File Management |  | 4.3. Creating and Editing Files |
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