Wild Cards
July 19, 1998
There are several tools that are useful
when submitting commands to the
kernel via the
shell.
These tools help make tasks more efficient. One such
tool is the wild card.
The wild cards that you will use most
often include the asterisk (*), the question mark (?) and
the brackets ([])
The asterisk is used to match any
character zero or more times. For example, if we modify
the "ls" command used in the last section, we can filter
the output for only files starting with "s" using the command
ls -l s*
The question mark on the other
hand, is used to match any single character. Thus
ls -l ???? will match any file with a name four characters long
such as temp or "temp"
Finally, brackets are used to specify
ranges or internal sets. Thus you can specify which
characters from within a set you are looking for such as in the
following case which matches any even number below 10: [02468]
Below is a table that shows some of the more
common uses for wildcards with the "ls" command
that you might use.
| Example |
Result |
| ls index* |
Matches any file beginning with
the characters "index" including index.html,
index.bak, index.cgi |
| ls *.html |
Matches any file ending in
".html" such as index.html or test.html. (Note however,
that this would not match index.html.bak. To do that you
would need *.html*) |
| ls a*.html |
matches all the HTML files starting
with the letter "a" |
| ls ?? |
Matches any file with a filename
of two characters such as "aa" or "bb" |
| ls ?.html |
Matches all HTML files with a single
character name such as a.html or 1.html. 12.html would
not match |
| ls [abcd]??.html |
Matches any file starting with
"a", "b", "c" or "d" followed by any two characters, and
followed by a .html ending. |
| ls part[0-9].doc |
Matches all .doc from
part 1 through part 9 such as part4.doc. |
| ls part[A-Z].doc |
Matches all .doc from
part A through part Z such as "partM.doc". Notice that
this is case sensitive so it would not match
"partm.doc". To do that, you would need
[a-z] or [a-zA-Z] |
Executing Utilities
Introduction to UNIX for Web Developers | Table of Contents
Input, Output, and Redirection
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