Wildcards
The * wildcard
The character * is called a wildcard, and will match
against none or more character(s) in a file (or directory) name. For example,
in your unixstuffdirectory,
type
% ls list*
This will list all files in
the current directory starting with list....
Try typing
% ls *list
This will list all files in
the current directory ending with ....list
The ? wildcard
The character ? will match exactly one character.
So ?ouse will match files like house and mouse, but not grouse.
Try typing
% ls ?list
Filename conventions
We should note here that a
directory is merely a special type of file. So the rules and conventions for
naming files apply also to directories.
In naming files, characters
with special meanings such as / * & % , should be avoided. Also, avoid using
spaces within names. The safest way to name a file is to use only alphanumeric
characters, that is, letters and numbers, together with _ (underscore) and .
(dot).
Good filenames
|
Bad filenames
|
project.txt
|
project
|
my_big_program.c
|
my big program.c
|
fred_dave.doc
|
fred & dave.doc
|
File names conventionally
start with a lower-case letter, and may end with a dot followed by a group of
letters indicating the contents of the file. For example, all files consisting
of C code may be named with the ending .c,
for example, prog1.c . Then in order to list all files
containing C code in your home directory, you need only type ls *.c in that directory.
Getting Help
On-line Manuals
There are on-line manuals
which gives information about most commands. The manual pages tell you which
options a particular command can take, and how each option modifies the
behaviour of the command. Type man command to read the manual page for a particular
command.
For example, to find out more
about the wc (word count) command, type
% man wc
Alternatively
% whatis wc
gives a one-line description
of the command, but omits any information about options etc.
Apropos
When you are not sure of the
exact name of a command,
% apropos
keyword
will give you the commands
with keyword in their manual page header. For example, try typing
% apropos copy
Summary
Command
|
Meaning
|
*
|
match any number of characters
|
?
|
match one character
|
man command
|
read the online manual page for a command
|
whatis command
|
brief description of a command
|
apropos keyword
|
match commands with keyword in their man pages
|
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