pgtclsh is a Tcl shell interface extended with PostgreSQL database access functions. (Essentially, it is tclsh with libpgtcl loaded.) Like with the regular Tcl shell, the first command line argument is a script file, any remaining arguments are passed to the script. If no script file is named, the shell is interactive.
A Tcl shell with Tk and PostgreSQL functions is available as pgtksh.
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.