Regular Expressions 101

Explanation

Pro

^start of line

Negative Lookahead(?! )

the literal (32₁₀ / 40₈ / 20₁₆)

Negative Lookahead(?!.* )

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

the literal text

Negative Lookahead(?!.* $)

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

the literal (32₁₀ / 40₈ / 20₁₆)

$end of line

Negated Character Class[^\s]

\sany whitespace character

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

$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.

25 tokens

^(?! )(?!.*  )(?!.* $)[^\s].*$

New

words with single spaces
 space at beginning
space at the end 
words  with  multiple  spaces

words with single spaces
 space at beginning
space at the end 
words  with  multiple  spaces