Regular Expressions 101

^start of line

Group 1((--(?P<HELP>help).*)|((?:-s|--separator)\s(?P<SEP>.*?)\s)?((?P<OP1>-?\d+))(\s(?P<OP2>-?\d+))?(\s(?P<OP3>-?\d+))?)

1st Alternative(--(?P<HELP>help).*)

Group 2(--(?P<HELP>help).*)

--the literal text --

Group HELP(?P<HELP>help)

helpthe literal text help (case sensitive)

.*any character (except for line terminators), repeated any number of times

2nd Alternative((?:-s|--separator)\s(?P<SEP>.*?)\s)?((?P<OP1>-?\d+))(\s(?P<OP2>-?\d+))?(\s(?P<OP3>-?\d+))?

Group 4((?:-s|--separator)\s(?P<SEP>.*?)\s)?

?repeats the group contents below at most once:

Non-Capturing Group(?:-s|--separator)

1st Alternative-s

-sthe literal text -s (case sensitive)

2nd Alternative--separator

--separatorthe literal text --separator (case sensitive)

\sany whitespace character

Group SEP(?P<SEP>.*?)

.*?any character (except for line terminators), repeated any number of times

\sany whitespace character

Group 6((?P<OP1>-?\d+))

Group OP1(?P<OP1>-?\d+)

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

Group 8(\s(?P<OP2>-?\d+))?

?repeats the group contents below at most once:

\sany whitespace character

Group OP2(?P<OP2>-?\d+)

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

Group 10(\s(?P<OP3>-?\d+))?

?repeats the group contents below at most once:

\sany whitespace character

Group OP3(?P<OP3>-?\d+)

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^((--(?P<HELP>help).*)|((?:-s|--separator)\s(?P<SEP>.*?)\s)?((?P<OP1>-?\d+))(\s(?P<OP2>-?\d+))?(\s(?P<OP3>-?\d+))?)$

New

-s T  10
--help
3 13 2
--separator T 3 11
wrong argument
-s test1