Unix Power Tools, 3rd Edition

Glossary

A - M

AIX

A version of Unix from the IBM Corporation.

argument

Zero or more characters passed to a program or function as a single unit. The shell breaks a command line into arguments by cutting it at unquoted whitespace.

array

An ordered collection of data items. An array has a single overall name; each item in it is called an element or member. For instance, the C shell stores its command search path in an array named path. The first array member is named $path[1], the second is $path[2], and so on. Some arrays are indexed from zero (e.g., C, Perl).

ASCII text file

Formally, a text file containing only ASCII characters. More commonly (in the U.S., at least), a file containing text that’s printable, viewable, and has no “binary” (non-ASCII) characters. ASCII characters use only seven of the bits in a (8-bit) byte.

backquote

The character `. Not the same as a single quote ('). Used in pairs, does command substitution.

backslash

The character \. In Unix, it changes the interpretation of the next character in some way. See also Section 27.18.

batch queue

A mechanism for sequencing large jobs. A batch queue receives job requests from users. It then executes the jobs one at a time. Batch queues go back to the earliest days of data processing. They are an extremely effective, if uncomfortable, way to manage system load.

bin directory

A directory for storing executable programs. See also Section 7.4.

binaries, binary file

A file with nontext characters. Often, a directly executable file that can ...