Chapter Summary

   

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Regular expressions are very useful in day-to-day work where you need to match character patterns. In this chapter, you learned how a UNIX command is executed. Position specifiers are used to match a pattern at the start or end of a line, and you learned the use of caret ^ and dollar $ position specifiers. Then you studied other meta characters and their use in regular expressions. The asterisk character is used to match any number of characters , including zero. The dot character matches one character at a time, including the new line character. Square brackets [] are used for specifying a range of characters. You also used word delimiters \< and \> . These are used to match a complete word during a text pattern matching process.

Extended regular expressions have some additional features and are used with commands like egrep and awk . They are able to incorporate logical OR operation while matching a text pattern.

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