Hyphen and underscore not compatible in sed

Question

I\'m having trouble getting sed to recognize both hyphen and underscore in its pattern string.

Does anyone know why

[a-z|A-Z|0-9|\\-|_]

Answer 1

As mentioned, you don't need anything to separate your ranges in a bracket expression. All that will do is adding | to the characters matched by the expression.

Then, to add a hyphen, you can put it as the first or last character in the expression:

[a-zA-Z0-9_-]

And finally, ranges like a-z don't necessarily mean abcd...xyz, depending on your locale. You could use a POSIX character class instead:

[[:alnum:]_-]

Where [:alnum:] corresponds to all alphanumeric characters of your locale. In the C locale, it corresponds to 0-9A-Za-z.