HP NonStop G-Series - Manual (Page 32)

Table 1 Selected OSS Shell Features (continued)
Description Feature
A feature that allows user-assigned values to be passed to the shell and to variables
in the command line. Parameter substitution
A feature that allows you to use a command’s output as if it was the value of a
variable. Command substitution
Mechanisms for trapping interruptions and other OSS signals. Signal trapping
A feature that allows values, attributes, and comparisons to be tested. Conditional expressions
A feature that allows you to run, monitor, and manage foreground and background
processes. Job control
The ability to group data and call it by a name. Arrays
Metacharacters
Table 2 lists shell metacharacters (characters that have special meaning to the shell).
Table 2 Shell Metacharacters
Description Metacharacter
Syntactic
Separates commands that are part of a pipeline. |
Runs the next command if the current command succeeds. &&
Runs the next command if the current command fails. ||
Separates commands that should be executed sequentially. ;
Separates elements of a case construct. ;;
Runs commands in the background. &
Groups commands to run as a separate process in a subshell. ( )
Groups commands without creating a subshell. { }
Filename
Separates the parts of a file’s pathname. /
Matches any single character except a leading dot. ?
Matches any sequence of characters except a leading dot. *
Matches any of the enclosed characters. [ ]
Specifies a home directory when used at the beginning of a filename. ~
Quotation
Specifies that the following character should be interpreted literally; that is, without its
special meaning to the shell. \
Specifies that any of the enclosed characters (except for the single-quotation-mark
character) should be interpreted literally; that is, without their special meaning to the
shell. '...'
Specifies that the $ (dollar sign), ` (grave accent), and \ (backslash) characters keep
their special meaning to the shell, while all other enclosed characters should be
interpreted literally to the shell; that is, without their special meaning to the shell. "..."
Input/Output
Redirects input. <
32 The OSS Shell