UNIX General Terms

Glossary of Common UNIX and General Computer Terms

This glossary provides definitions for many of the terms you may see while using the DIGITAL UNIX documentation. Although the majority of terms deal with the UNIX environment, you will also find other common terms you will encounter; for example, words releated to the Internet.

Y
yacc (Yet Another Compiler-Compiler)
A program for generating parsers (programs that can interpret their input in a 
rational manner). The output from yacc is a C language program. The yacc
program is usually used to generate parsers for interpreting the output of a lexgenerated front end. 
See also lex, parser
younger file
For the make utility, a dependency file that has changed more recently than its 
target.

X
X/Open Transport Interface
See XTI (X/Open Transport Interface)
XPT
A layer of software that SCSI peripheral drivers use to originate the execution of 
CAM (Common Access Method) functions. 
XTI (X/Open Transport Interface)
Protocol-independent, transport-layer interface for applications. XTI consists of a 
series of C language functions based on the Transport Layer Interface (TLI), which
in turn was based on the transport service definition for the OSI model. 

W
wildcard character
A metacharacter that is used to allow wildcard matching in file names or regular 
expressions. 
See also metacharacter, regular expression
word identifier
A piece of a command line delimited by blanks and recognized as a unique entity 
by the shell. Used to save keystrokes. By using word identifiers, a user can select 
part of a previous command line for use in the current command line. 
wordlist

V
variable
In programming languages, shell scripts, command procedures, and the like, a 
symbol whose value is allowed to change. 
variable expansion
The replacement of the variable identifier with its associated strings in a shell 
command line. 
variable modifier
A symbol referring to part of a variable, usually under the assumption that its 
value is a pathname. 
version control file

U
UDP (User Datagram Protocol)
The Internet Protocol that allows application programs on remote machines to 
send datagrams to one another. UDP uses IP to deliver the datagrams. 
UFS (UNIX File System)
TBS 
uid, UID
See user ID
ULTRIX
One of two UNIX operating system products available from DIGITAL Equipment 
Corporation. The ULTRIX operating system runs on VAX and RISC computers, 
whereas DIGITAL UNIX runs on Alpha systems. 

T
tail
A command that displays a user-specifiable number of lines at the end of a text 
file. 
See also head
tar program
A program that makes portable copies of files for archiving or transfer to another 
system. By default, the tar program writes its archive files on the system's 
primary magnetic tape unit. 
target
In the make utility, an entity to be built from its dependents. An executable 

S
SCCS library
The directory in which Source Code Control System (SCCS) s-files and p-files are 
stored. 
SCCS (Source Code Control System)
A set of programs for managing program and documentation source files so that 
any revision of a given file can be retrieved. Revisions to a file are stored as a 
series of incremental changes (deltas) applied to the original version instead of as
complete copies of all the versions. The system provides locking mechanisms so 

R
raw mode
The condition of a device driver in which the driver does not interpret the data 
passing through it. For example, a UNIX terminal driver operating in raw mode 
passes a Return character from the terminal directly to the system. 
See also cooked mode
raw socket
A socket that provides privileged users access to internal network protocols and 
interfaces. These socket types can be used to take advantage of protocol features

Q
query
1. The action of searching data for desired information. 
2. In data communications, the process by which a master station asks a slave 
station to identify itself and to give its status. 
3. In interactive systems, an operation at a terminal or workstation that elicits a 
response from the system. 
4. A request for information from a file based on specific conditions. 
queue