shell script: pattern match (模式识别)

关键词： Linux， pattern match, 模式识别， 匹配
以下摘自：书名： Linux Shell Scripting with Bash ，作者：Ken O. Burtch
  ?(pattern-list)—Matches zero or one occurrence of the given patterns
  *(pattern-list)—Matches zero or more occurrences of the given patterns
  +(pattern-list)—Matches one or more occurrences of the given patterns
  @(pattern-list)—Matches exactly one of the given patterns
  !(pattern-list)—Matches anything except one of the given patterns

例子：
COMPANY=”AAA Ballistics Ltd”
if [[ $COMPANY = +(A)*Ltd ]] ; then
   printf “The company name begins with one or more A’s and finishes with Ltd\n”
fi

其它：
  [:alnum:]—Alphanumeric
  [:alpha:]—Alphabetic
  [:ascii:]—ASCII characters
  [:blank:]—Space or tab
  [:cntrl:]—Control characters
  [:digit:]—Decimal digits
  [:graph:]—Non-blank characters
  [:lower:]—Lowercase characters
  [:print:]—Non-control characters
  [:punct:]—Punctuation characters
  [:space:]—Whitespace
  [:upper:]—Uppercase characters
  [:xdigit:]—Hexadecimal digits
例子：
COMPANY=”2nd Rate Solutions”
if [[ $COMPANY = [[:digit:]]*]] ; then
   printf “Company name starts with a digit\n”
fi
例子：
$ ls *+(.c|.h)
actions.c coledit.c config.c dump.c form.c form.h main.c