- 论坛徽章:
- 8
|
lion0124 发表于 2012-04-23 16:23
回复 2# waker
- 7.1 Pattern Elements
- Regexp Patterns: Using regexps as patterns.
- Expression Patterns: Any expression can be used as a pattern.
- Ranges: Pairs of patterns specify record ranges.
- BEGIN/END: Specifying initialization and cleanup rules.
- BEGINFILE/ENDFILE: Two special patterns for advanced control.
- Empty: The empty pattern, which matches every record.
- Patterns in awk control the execution of rules—a rule is executed when its pattern matches the current input record. The following is a summary of the types of awk patterns:
- /regular expression/
- A regular expression. It matches when the text of the input record fits the regular expression. (See Regexp.)
- expression
- A single expression. It matches when its value is nonzero (if a number) or non-null (if a string). (See Expression Patterns.)
- pat1, pat2
- A pair of patterns separated by a comma, specifying a range of records. The range includes both the initial record that matches pat1 and the final record that matches pat2. (See Ranges.)
- BEGIN
- END
- Special patterns for you to supply startup or cleanup actions for your awk program. (See BEGIN/END.)
- BEGINFILE
- ENDFILE
- Special patterns for you to supply startup or cleanup actions to done on a per file basis. (See BEGINFILE/ENDFILE.)
- empty
- The empty pattern matches every input record. (See Empty.)
复制代码 |
|