Carets in Regular Expressions

^ only means "not the following" when inside and at the start of [], so [^...].

When it's inside [] but not at the start, it means the actual ^ character.

When it's escaped (\^), it also means the actual ^ character.

In all other cases it means start of the string / line (which one is language / setting dependent).

So in short:

• [^abc] -> not a, b or c
• [ab^cd] -> a, b, ^ (character), c or d
• \^ -> a ^ character
• Anywhere else -> start of string / line.

So ^[b-d]t$ means:

• Start of line
• b/c/d character
• t character
• End of line