z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

\ This character turns off the special meaning of metacharacters. For
example, \. only matches a dot character. Note that \\ matches a literal \
character. Also note the special case of “\d” described in the following
paragraph.
\d For d representing any single decimal digit (from 1 to 9), this pattern is
equivalent to the string matching the dth expression enclosed within the ()
characters (or \(\) for some commands) found at an earlier point in the
regular expression. Parenthesized expressions are numbered by counting (
characters from the left.
Constructs of this form can be used in the replacement strings of
substitution commands (for example, the sub function of awk), to stand for
constructs matched by parts of the regular expression.
regexp*
A regular expression regexp followed by * matches a string of zero or more
strings that would match regexp. For example, A* matches A, AA, AAA and
so on. It also matches the null string (zero occurrences of A). ).
regexp+
A regular expression regexp followed by + matches a string of one or more
strings that would match regexp.
regexp?
A regular expression regexp followed by ? matches a string of one or zero
occurrences of strings that would match regexp.
char{n} | char\{n\}
In this expression (and the ones to follow), char is a regular expression that
stands for a single character—for example, a literal character or a period
(.). Such a regular expression followed by a number in brace brackets
stands for that number of repetitions of a character. For example, X\{3\}
stands for XXX. In basic regular expressions, in order to reduce the number
of special characters, { and } must be escaped by the \ character to make
them special, as shown in the second form (and the ones to follow).
char{min,} | char\{min,\}
When a number, min, followed by a comma appears in braces following a
single-character regular expression, it stands for at least min repetitions of a
character. For example, X\{3,\} stands for at least three repetitions of X.
char{min,max} | char\{min,max\}
When a single-character regular expression is followed by a pair of
numbers in braces, it stands for at least min repetitions and no more than
max repetitions of a character. For example, X\{3,7\} stands for three to
seven repetitions of X.
regexp1 | regexp2
This expression matches either regular expression regexp1 or regexp2.
(regexp) | \(regexp\)
This lets you group parts of regular expressions. Except where overridden
by parentheses, concatenation has the highest precedence. In basic regular
expressions, in order to reduce the number of special characters, ( and )
must be escaped by the \ character to make them special, as shown in the
second form.
Several regular expressions can be concatenated to form a larger regular
expression.
regexp
Appendix C. Regular Expressions (regexp) 887