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
unixstuff directory, type
This will list all files in the current directory starting with
This will list all files in the current directory ending with
The character ? will match exactly one character. So
ls ?ouse will match files like
mouse, but not
grouse. Try typing
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
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.
Beware: some applications give the same name to all the output files they
generate. For example, some compilers, unless given the appropriate
option, produce compiled files named
you forget to use that option, you are advised to rename the compiled file
immediately, otherwise the next such file will overwrite it and it will
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
(word count) command, type
gives a one-line description of the command, but omits any information about options etc.
||match any number of characters|
||match one character|
read the online manual page for |
brief description of |
match commands with |