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+ | =====Linux Tutorial Four===== | ||
+ | ====4.1 Wildcards==== | ||
+ | |||
+ | The characters * and ? | ||
+ | |||
+ | 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 **list....** | ||
+ | |||
+ | Try typing | ||
+ | |||
+ | < | ||
+ | |||
+ | This will list all files in the current directory ending with **....list** | ||
+ | |||
+ | The character ? will match exactly one character. | ||
+ | So ls **?ouse** will match files like **house** and **mouse**, but not **grouse**. | ||
+ | Try typing | ||
+ | |||
+ | < | ||
+ | |||
+ | ====4.2 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). | ||
+ | |||
+ | 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 a.out. Should you forget to use that option, you are advised to rename the compiled file immediately, | ||
+ | |||
+ | ====4.3 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 | ||
+ | |||
+ | < | ||
+ | |||
+ | Alternatively | ||
+ | |||
+ | < | ||
+ | |||
+ | 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, | ||
+ | |||
+ | < | ||
+ | |||
+ | will give you the commands with keyword in their manual page header. For example, try typing | ||
+ | |||
+ | < | ||
+ | |||
+ | ====Summary==== | ||
+ | ^ Command | ||
+ | | ** * ** | match any number of characters | ||
+ | | **?** | match one character | ||
+ | | **man command** | ||
+ | | **whatis command** | ||
+ | | **apropos keyword** | ||