Load a script into the scripts cache, without executing it. After the specified command is loaded into the script cache it will be callable using EVALSHA with the correct SHA1 digest of the script, exactly like after the first successful invocation of EVAL.
The script is guaranteed to stay in the script cache forever (unless SCRIPT
FLUSH is called).
The command works in the same way even if the script was already present in the script cache.
Please refer to the EVAL documentation for detailed information about Redis Lua scripting.
*Return value
Bulk string reply This command returns the SHA1 digest of the script added into the script cache.