There is no single fully reversible textual format for scripts.

BitcoinQT uses this format in its unit tests:

-?[0-9]+ is interpreted as int64. If it's from -1 to 16, interprets as "OP_", otherwise pushes bignum data. '[^']*' is interpreted as ASCII string 0x[0-9a-fA-F]+ is interpreted as a raw binary to be inserted in script (not just data) (OP_)? is replaced by an opcode byte.