Re: regexp not behaving as expected.

[Neil R. Ormos]

slipbits wrote:

> I've got a problem with my use of regexp w/gawk
> and I can't seem to find out what I did
> wrong. When the first three characters on a line
> are "CC:" or "  CC:" it is sometimes
> recognized, and sometimes not recognized, and I
> can't figure out what I've done wrong.

>
> The program is: [...]
>
>     if ($0 ~ /^([:space:]\r)*(Subject|Date|CC|BCC|From|To):/) {

Try changing

  [:space:]

in the two regexps to

  [[:space:]]


Quoting the manual,

| A character class is only valid in a regexp
| *inside* the brackets of a bracket expression.

  <https://www.gnu.org/software/gawk/manual/gawk.html#Bracket-Expressions>

The outer pair of brackets establish the bracket expression.

The inner pair of brackets are part of the "Character Class".

Good luck!