The escape character is a backslash (\
). You can
use it to escape meta characters to use them in their plain character
form.
In the following examples literal 'E' and 'F' denote any expression, whether a pattern or a character.
Start a capturing subexpression.
End a capturing subexpression.
Disjunction, match either E or F (inclusive). E is preferred if both match.
Act as Kleene star, match E zero or more times.
Closure, match E one or more times.
Option, match E optionally once.
Match any character except for newline characters (\n,
\f, \r) and the NULL
byte.
Match E exactly n times.
Match E n or more times.
Match E at most n times.
Match E no less than n times and no more than m times.
Start a character set, see Character Sets For Egrep.
Match the empty string at the end of the input or at the end of a line.
Match the empty string at the start of the input or at the beginning of a line.