HP-UX Reference (11i v2 07/12) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

introduction(9) introduction(9)
appropriate manpages: sh-posix(1) for the POSIX shell, ksh(1) for the Korn shell, or csh(1) for the C shell.
The Current Directory
HP-UX has a file system arranged in a hierarchy of directories. When the system administrator gave you a
user name, he or she also created a directory for you (ordinarily with the same name as your user name,
and known as your login or home directory). When you log in, that directory becomes your current or work-
ing directory, and any file name you type is assumed to be in that directory by default. Because you are the
owner of this directory, you have full permission to read, write, alter, or destroy its contents. The permis-
sions you have for other directories and files will have been granted or denied to you by their respective
owners, or by the system administrator. To change the current working directory use cd(1).
Path Names
To refer to files not in the current directory, you must use a path name. Full (absolute) path names begin
with
/, which is the name of the root directory of the whole file system. After the slash comes the name of
each directory containing the next subdirectory (followed by a
/), until finally the file name is reached (for
example,
/usr/ae/filex
refers to file filex in directory ae, while ae
is itself a subdirectory of usr;
usr is a subdirectory of the root directory). See glossary(9) for a formal definition of path name.
If your current directory contains subdirectories, the path names of files in them begin with the name of
the corresponding subdirectory (without a prefixed
/). Generally, a path name can be used anywhere a file
name is required.
Important commands that modify the contents of directories are
cp, mv, and rm which respectively copy,
move (that is, rename, relocate, or both), and remove files. To determine the status of files or the contents
of directories, use the
ls command. Use mkdir to make directories, rmdir to destroy them, and mv
to
rename them (see cp(1), ls(1), mkdir(1), mv(1), rm(1), and rmdir(1)).
Writing a Program
To enter the text of a source program into an HP-UX file, use a text editing program such as
vi, ex,ored
(see vi(1), ex(1), and ed(1)). The three principal languages available under HP-UX are C (see cc_bundled(1)
and cc(1)), FORTRAN (see f77(1)), and Pascal (see pc(1)). After the program text has been entered with the
editor and written into a file (whose name has the appropriate suffix), you can give the name of that file to
the appropriate language processor as an argument. Normally, the output of the language processor will be
left in a file named
a.out in the current directory. Since the results of a subsequent compilation may also
be placed in a.out, thus overwriting the current output, you may want to use mv
to give the output a
unique name. If the program is written in assembly language, you will probably need to link library sub-
routines with it (see ld(1)). FORTRAN, C, and Pascal call the linker automatically.
When you have gone through this entire process without encountering any diagnostics, the resulting pro-
gram can be run by giving its name to the shell in response to the prompt.
Your programs can receive arguments from the command line just as system programs do by using the argc
and argv parameters. See the supplied C tutorial for details.
Text Processing
Almost all text is entered through a text editor. The editor preferred above all others provided with HP-UX
is the
vi editor. For batch-processing text files, the
sed editor is very efficient. Other editors are used
much less frequently. The
ex editor is useful for handling certain situations while using vi but most other
editors are rarely used except in various scripts.
The following editors are the same program masquerading under various names: vi, view, and vedit
(see vi(1)) and ex and edit (see ex(1)). For information about the sed stream editor, see sed(1). The ed
line editor is described in ed(1).
The commands most often used to display text on a terminal are cat, more, and pr (see cat(1), more(1),
and pr(1)). The cat command simply copies ASCII text to the terminal, with no processing at all. The
more command displays text on the terminal a screenful at a time, pausing for an acknowledgement from
the user before continuing. The pr command paginates text, supplies headings, and has a facility for mul-
ticolumn output. pr is most commonly used in conjunction with the lp command (see lp(1)) to pipe for-
matted text to a line printer.
Interuser Communication
Certain commands provide interuser communication. Even if you do not plan to use them, it could be
beneficial to learn about them, because someone else may direct them toward you. To communicate with
another user that is currently logged in, you can use write to transfer text directly to that user’s terminal
270 Hewlett-Packard Company − 6 − HP-UX 11i Version 2: December 2007 Update