source - executes commands in a file without adding them to history
source [-h] name [arg ...]
This command is a C-shell built-in command.
The shell reads and executes commands from name. The commands are not placed on the history list. If arguments (arg) are given, they are placed in argv. You can nest source commands; if they are nested too deeply, however, the shell might run out of file descriptors. An error in a source at any level terminates all nested source commands. With -h, commands are placed on the history list instead of being executed, much like history -L.