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

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glossary(9) glossary(9)
shell program
See shell script.
shell script
A sequence of shell commands and shell programming language constructs stored in a file and invoked as a
user command (program). No compilation is needed prior to execution because the shell recognizes the
commands and constructs that make up the shell programming language. A shell script is often called a
shell program or a command file. See the Shells User Guide.
shmid
See shared memory identifier.
signal
A software interrupt sent to a process, informing it of special situations or events. Also, the event itself.
See signal(2).
single-user state
A condition of the HP-UX operating system in which the system console provides the only communication
mechanism between the system and its user. By convention, single-user state is usually specified by
init(1M) as run-level
S or s. Do not confuse single-user state, in which the software is limiting a mul-
tiuser system to a single-user communication, with a single-user system, which can never communicate
with more than one fixed terminal. See also multiuser state.
slash
The literal character /.Apath name consisting of a single slash resolves to the root directory of the
process. See also path name resolution.
solidus
See slash.
source code
The fundamental high-level information (program) written in the syntax of a specified computer language.
Object (machine-language) code is derived from source code. When dealing with an HP-UX shell command
language, source code is input to the command language interpreter. The term shell script is
synonymous with this meaning. When dealing with the C Language, source code is input to the cc(1)
command. Source code can also refer to a collection of sources meeting any of the above conditions.
special file
A file associated with an I/O device. Often called a device file. Special files are read and written the same
as ordinary files, but requests to read or write result in activation of the associated device. Due to con-
vention and consistency, these files should always reside in the
/dev directory. See also file.
special processes
Processes with certain (small) process IDs are special. On a typical system, the IDs of 0, 1, and 2 are
assigned as follows: Process 0 is the scheduler. Process 1 is the initialization process
init, and is the
ancestor of every other process in the system. It is used to control the process structure. On paging sys-
tems with virtual memory, process 2 is the paging daemon.
SS/80
See CS/80.
standard error
The destination of error and special messages from a program, intended to be used for diagnostic messages.
The standard error output is often called stderr, and is automatically opened for writing on file descriptor
2 for every command invoked. By default, the user’s terminal is the destination of all data written to
stderr, but it can be redirected elsewhere. Unlike standard input and standard output, which are never
used for data transfer in the "wrong" direction, standard error is occasionally read. This is not recom-
mended practice, since I/O redirection is likely to break a program doing this.
standard input
The source of input data for a program. The standard input file is often called stdin, and is automatically
opened for reading on file descriptor 0 for every command invoked. By default, the user’s terminal is the
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