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

Appendix C. Regular Expressions (regexp)
Many z/OS shell commands match strings of text in text files using a type of pattern
known as a regular expression. A regular expression lets you find strings in text files
not only by direct match, but also by extended matches, similar to, but much more
powerful than the filename patterns described in sh.
The newline character at the end of each input line is never explicitly matched by
any regular expression or part thereof.
expr and ed take basic regular expressions; all other shell commands accept
extended regular expressions. grep and sed accept basic regular expressions, but
will accept extended regular expressions if the –E option is used.
Regular expressions can be made up of normal characters or special characters,
sometimes called metacharacters. Basic and extended regular expressions differ
only in the metacharacters they can contain.
The basic regular expression metacharacters are:
¬ $ . * \( \) [ \{ \} \
The extended regular expression metacharacters are:
| ¬ $ . * + ? ( ) [ { } \
These have the following meanings:
. A dot character matches any single character of the input line.
¬ The ¬ character does not match any character but represents the beginning
of the input line. For example, ¬A is a regular expression matching the letter
A at the beginning of a line. The ¬ character is only special at the beginning
of a regular expression, or after a ( or |.
$ This does not match any character but represents the end of the input line.
For example, A$ is a regular expression matching the letter A at the end of
a line. The $ character is only special at the end of a a regular expression,
or before a ) or |.
[bracket-expression]
A bracket expression enclosed in square brackets is a regular expression
that matches a single character, or collation element. This bracket
expression applies not only to regular expressions, but also to pattern
matching as performed by the fnmatch() function (used in filename
expansion).
v If the initial character is a circumflex (o), then this bracket expression is
complemented. It matches any character or collation-element except for
the expressions specified in the bracket expression. For pattern
matching, as performed by the fnmatch function, this initial character is
instead ! (the exclamation mark).
v If the first character after any potential circumflex is either a dash (-), or
a closing square bracket (]), then that character matches exactly that
character—that is, a literal dash or closing square bracket.
v You can specify collation sequences by enclosing their name inside
square brackets and periods. For example, [.ch.] matches the
multicharacter collation sequence ch (if the current language supports
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