Glossary of Unix programming

absolute path
The complete pathname to a file starting at the root directory /.

abstraction
Scripts that use abstraction retain the same basic flow by placing the conditional execution statements within functions. When a function is called, it makes a decision as to what commands execute for a given platform.

anchoring expression
Normally any part of a line will be matched by a regular expression. To match expressions that either begin or end a line, you need to anchor the regular expression. The ^ character anchors regular expressions to the beginning of a line, whereas the $ character anchors regular expressions to the end of a line.

argument
Command modifiers that change the behavior of a command. In the shell, they are specified after a command’s name.

array variable
A mechanism available in bash and ksh for grouping scalar variables together. The scalar variables stored in an array are accessed using a single name in conjunction with a number. This number is referred to as an index.

awk
The awk command is a power pattern matching language that allows you to modify input lines by manipulating the fields they contain.