Familiar but without hands-on experience. Read some reference manuals on it and code samples.
I recognized right away that the span and break pattern-matching operators of Snobol must be the inspiration behind C library names like strspn and strpbrk.
When I was in high school, I stumbled across the source code for cc on the UIC mainframe. Part of it was in either Snobol or Spitbol (I don't remember now) and I remember going to the library to get a book on the language to learn enough to be able to decipher the code.
I used it to write a go-moku (5-in-a-row) playing program in an AI course and got an A when it beat the professor.