Regular Expressions 101

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/
(\s[a-zA-Z]{6}[0-9]{8}\s){1}
/
g
1st Capturing Group
(\s[a-zA-Z]{6}[0-9]{8}\s){1}
{1} matches the previous token exactly one time (meaningless quantifier)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
Match a single character present in the list below
[a-zA-Z]
{6} matches the previous token exactly 6 times
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
Match a single character present in the list below
[0-9]
{8} matches the previous token exactly 8 times
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
g

Test String