HP-UX Reference (11i v1 05/09) - 5 Miscellaneous Topics (vol 9)

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regexp(5) regexp(5)

The concatenation of one or more patterns matching a single character with one or

more asterisks is a valid pattern. In such patterns, each asterisk matches a string of

zero or more characters, up to the ﬁrst character that matches the character following

the asterisk in the pattern.

For example, the pattern a∗∗d matches the strings ad, abd, and abcd; but not the

string abc. When an asterisk is the ﬁrst or last character in a pattern, it matches

zero or more characters that precede or follow the characters matched by the

remainder of the pattern. For example, the pattern a∗∗d∗∗ matches the strings ad,

abcd, abcdef, aaaad, and adddd; the pattern ∗∗a∗∗d matches the strings ad, abcd,

efabcd, aaaad, and adddd.

Rule Qualiﬁcation for Patterns Used for Filename Expansion

The rules described above for pattern matching are qualiﬁed by the following rules when the pattern

matching notation is used for ﬁlename expansion by sh(1), csh(1), ksh(1), and make(1).

If a ﬁlename (including the component of a pathname that follows the slash (/ ) character) begins with

a period ( . ), the period must be explicitly matched by using a period as the ﬁrst character of the pat-

tern; it cannot be matched by either the asterisk special character, the question mark special charac-

ter, or a bracket expression. This rule does not apply to make(1).

The slash character in a pathname must be explicitly matched by using a slash in the pattern; it can-

not be matched by either the asterisk special character, the question mark special character, or a

bracket expression. For make(1) only the part of the pathname following the last slash character can

be matched by a special character. That is, all special characters preceding the last slash character

lose their special meaning.

Speciﬁed patterns are matched against existing ﬁlenames and pathnames, as appropriate. If the pat-

tern matches any existing ﬁlenames or pathnames, the pattern is replaced with those ﬁlenames and

pathnames, sorted according to the collating sequence in effect. If the pattern does not match any

existing ﬁlenames or pathnames, the pattern string is left unchanged.

If the pattern begins with a tilde ( ˜) character, all of the ordinary characters preceding the ﬁrst slash

(or all characters if there is no slash) are treated as a possible login name. If the login name is null

(i.e., the pattern contains only the tilde or the tilde is immediately followed by a slash), the tilde is

replaced by a pathname of the process’s home directory, followed by a slash. Otherwise, the combina-

tion of tilde and login name are replaced by a pathname of the home directory associated with the

implementation-deﬁned. This rule does not apply to sh(1) or make(1).

If the pattern contains a $ character, variable substitution can take place. Environmental variables

can be embedded within patterns as:

$name

or:

${name }

Braces are used to guarantee that characters following name are not interpreted as belonging to

name. Substitution occurs in the order speciﬁed only once; that is, the resulting string is not exam-

ined again for new names that occurred because of the substitution.

Rule Qualiﬁcation for Patterns Used in the case Command

The rules described above for pattern matching are qualiﬁed by the following rule when the pattern match-

ing notation is used in the case command of sh(1) and ksh(1).

Multiple alternative patterns in a single clause can be speciﬁed by separating individual patterns with

the vertical bar character ( |); strings matching any of the patterns separated this way will cause the

corresponding command list to be selected.