I may be misunderstanding the specification, but I believe he wants to include non-digits but exclude newlines. I think the easiest way is [^\d\n], but I would prefer to explicitly include what is allowed. He mentioned in his OP the following separators: .-:. That being the case, the character class would be [.:-].

He mentioned in his OP the following separators: .-:. That being the case, the character class would be [.:-].

gautamparimoo:
davido is absolutely right, but as you are apparently a regex tyro, it is prudent to mention a major pitfall lurking here.

The  '-' character is special in a character class: it denotes a range of characters. Taken in its originally stated order,  [.-:] would match all characters in the range from '.' to ':' inclusive, which includes all decimal digits and '/' (assuming the ASCII character set). To unmajick the '-' in a character class, put it as the first or last character, or escape it:
    [-.:]  [.:-]  [.\-:]
See perlre, perlrequick (esp. Using character classes), and perlrecharclass (esp. Bracketed Character Classes, Special Characters Inside a Bracketed Character Class, Character Ranges and Negation).