| POSIX Character Class | Equivalence |
|---|---|
[:digit:] |
0-9 |
[:xdigit:] |
a-fA-F0-9 |
[:lower:] |
a-z |
[:upper:] |
A-Z |
[:alpha:] |
a-zA-z |
[:alnum:] |
a-zA-Z0-9 |
[:blank:] |
\t |
[:space:] |
^\f\n\r\t\v |
[:cntrl:] |
ASCII 0~31 + ASCII 127 |
[:print:] |
Any printable character |
[:graph:] |
Any printable character but space |
[:punct:] |
Any character besides [:alnum:] and [:cntrl:] |