AT&T UNIX™PC Unix System V Users Manual - tenox

INTRO (2) INTRO ( 2)
ProcO is the scheduler. Procl is the initialization process (init).
Procl is the ancestor of every other process in the system and is
used to control the process structure.
File Name.
Names consisting of 1 to 14 characters may be used to name an
ordinary file, special file or directory.
These characters may be selected from the set of all character
values excluding \0 (null) and the ASCII code for I (slash).
Note that it is generally unwise to use *, ?, [, or ] as part of file
names because of the special meaning attached to these characters
by the shell. See sh( 1). Although permitted, it is advisable to
avoid the use of unprintable characters in file names.
Path Name and Path Prefix
A path name is a null-terminated character string starting with an
optional slash (/), followed by zero or more directory names
separated by slashes, optionally followed by a file name.
More precisely, a path name is a null-terminated character string
constructed as follows:
::=l II
::=l /
::= II I
where is a string of 1 to 14 characters other than
the ASCII slash and null, and is a string of 1 to 14
characters (other than the ASCII slash and null) that names a
directory.
If a path name begins with a slash, the path search begins at the
root directory. Otherwise, the search begins from the current
working directory.
A slash by itself names the root directory.
Unless specifically stated otherwise, the null path name is treated
as if it named a non-existent file.
Directory .
Directory entries are called links. By convention, a directory contains
at least two links, • and .• , referred to as dot and dot-dot
respectively. Dot refers to the directory itself and dot-dot refers
to its parent directory.
Root Directory and Current Working Directory .
Each process has associated with it a concept of a root directory
and a current working directory for the purpose of resolving path
name searches. A process's root directory need not be the root
directory of the root file system, and is determined by the userid
entry in /etc/ passwd. The working directory for each process is
determined either by cd( 1) or chdir(2).
File Access Permissions.
Read, write, and execute/search permissions on a file are granted
to a process if one or more of the following are true:
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