Regular Expressions
Character | Definition | Example | Result |
---|---|---|---|
^ | Start of a string | ^abc | abc, abcd, abc1 |
$ | End of a string | abc$ | abc, rasabc, 2aabc |
. | Any character except newline | a.c | abc, acc, a1c |
Alteration | a | ||
{...} | Explicit quantity of preceding character | ab{2}c | abbc |
[...] | Explicit set of characters to match | a[bB]c | abc,aBc |
[a-z0-9] | One lower case characters or number | a[a-z0-9]c | aac,a1c |
(...) | Group of characters | (abc){2} | abcabc |
* | Null or more of the preceding characters | a*bc | bc, abc, aabc, aaaabc |
+ | One or more of the preceding character | a+bc | abc, aabc |
? | Null or one of the preceding character | a?bc | bc, abc |
^$ | Empty string |
- Not all regular expressions are supported by
grep
. As alternative can be usedegrep