Built-in commands pertain to the interpreter, and have no relation to simulation.
Help on command or category cmd. `help all' gives a list of all commands available in all categories. `help help' tells you how to use help.
Print output to stdout. Note: multiple spaces in output are compacted into single spaces by the interpreter's tokenizer.
Repeat a command cmd a fixed number of times, n. If there are any errors in during command processing, the loop will terminate early with a diagnostic message.
Open an interactive subshell of the interpreter, by re-opening the standard input stream. This is useful when you want to break in the middle of a non-interactive script and let the user take control temporarily before returning control back to the script. Ctrl-D sends the EOF signal to exit the current interactive level of input and return control to the parent.
Shell escape. Execute shell-cmd in parent shell, like the `system' library function, e.g. `!date'. Note: this preserves the rest of the line after the `!' verbatim.
The following commands are related to command aliases. Every command line given to the interpreter recursively expands the first token if it has a known alias. Aliases may reference to other aliases in the first token. The interpreter is smart enough to catch cyclic aliases and report an error.
Defines an alias, whereby the interpreter expands cmd into args before interpreting the command. args may consist of multiple tokens. This is useful for shortening common commands.
The following command is useful for showing each executed command.