Linux Regular Expressions

By:    Updated: February 27,2017

Linux Special characters in regular expressions

 

 Symbol  What it matches or does
 .  Matches any character
 [chars]  Matches any character from a given set
 [^chars]  Matches any character not in a given set
 ^  Matches the beginning of a line
 $  Matches the end of a line
 \w  Matches any “word” character (same as [A-Za-z0-9_])
 \W  Matches any character except “word” (same as [^A-Za-z0-9_])
 \s  Matches any whitespace character (same as [ \f\t\n\r])
 \S  Matches any character except whitespace (same as [^ \f\t\n\r])
 \d  Matches any digit (same as [0-9])
 \D  Matches any character except digit (same as [^0-9])
 \b  Matches a word boundary, 'py\b' matches 'py', 'py.', or 'py!', but not 'python', 'py1', 'py2'
 \B  Matches aposition that is not a word boundary, 'py\B' matches 'python', 'py1', 'py2', but not 'py', 'py.', or 'py!'
 |  Matches either the element to its left or the one to its right
 (expr)  Limits scope, groups elements, allows matches to be captured
 ?  Allows zero or one match of the preceding element
 *  Allows zero, one, or many matches of the preceding element
 +  Allows one or more matches of the preceding element
 {n}  Matches exactly n instances of the preceding element
 {min,}  Matches at least min instances (note the comma)
 {min,max}  Matches any number of instances from min to max
 \f  Matches a form feed, Used to instruct to start a new page
 \t  Matches a tab
 \n  Matches a new line
 \r  Matches a carriage return

 

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