How to match "command line argument" style strings with regex?

Question

I'm trying to validate a string I use in one of my applications, and the structure of it is basically the same as linux command line arguments.

E.G -m -b -s etc...

I'm basically trying to make the pattern;

• No space at the beginning but allow spaces inbetween words.
• There must be a space before a - if it isn't the first -.
• There should be no limit to how many you can enter as long as they fit the pattern. For example these would all be fine; -m -fd -optional but something like this wouldnt be; -m-fd teststring

I managed to get as far as ^-[a-zA-Z]\s but I'm not sure how to make this repeat! This also doesn't work on flags longer than 1 character and also has some issues with spaces!

Answer 1

To match and validate such a line you could use

^-[^\s-][^-]*(?:\s-[^\s-][^-]*)*$

See the regex demo.

To extract each option, you may use

(?<!\S)-[^\s-][^-]*

See this regex demo.

Details

• ^ - start of a string
• - - a hyphen
• [^\s-][^-]* - any char other than whitespace and - and then 0 or more chars othee than -
• (?:\s-[^\s-][^-]*)* - 0 or more repetitions of
  • \s - a whitespace
  • - - a hyphen
  • [^\s-][^-]* - any char other than whitespace and - and then 0 or more chars othee than -
• $ - end of string.