Table 2-2. Variables defined by tclsh and wish.
| argc | The number of command-line arguments. |
| argv | A list of the command-line arguments. |
| argv0 | The name of the script being executed. If being used interactively, argv0 is the name of the shell program. |
| embed_args | The list of arguments in the <EMBED> tag. Tcl applets only. See page 298. |
| env | An array of the environment variables. See page 117. |
| tcl_interactive | True (one) if the tclsh is prompting for commands. |
| tcl_library | The script library directory. |
| tcl_patchLevel | Modified version number, e.g., 8.0b1. |
| tcl_platform | Array containing operating system information. See page 182. |
| tcl_prompt1 | If defined, this is a command that outputs the prompt. |
| tcl_prompt2 | If defined, this is a command that outputs the prompt if the current command is not yet complete. |
| tcl_version | Version number. |
| auto_path | The search path for script library directories. See page 162. |
| auto_index | A map from command name to a Tcl command that defines it. |
| auto_noload | If set, the library facility is disabled. |
| auto_noexec | If set, the auto execute facility is disabled. |
| geometry | (wish only). The value of the -geometry argument. |
