'''[http://www.tcl.tk/man/tcl/TclCmd/tclvars.htm%|%tclvars]''', a page in the [manpages%|%official documentation], describes the built-in Tcl variables ** See Also ** [Magic names]: [Tcl syntax]: ** Documentation ** [http://www.tcl.tk/man/tcl/TclCmd/tclvars.htm%|%official reference]: ** Description ** `[argc%|%$argc]`: the number of arguments the script was called with. `[argv%|%$argv]`: a list of arguments passed to the script. Unlike [C], `$[argv]` does not include the name of the application itself among the argument list. For that, there is `$[argv0]`. `[argv0%|%$argv0]`: the name of the interpreter itself `$auto_execs`: Used by `[auto_execok]` to record information about whether particular commands exist as executable files. `[auto_index%|%$auto_index]`: Used by `[auto_load]` to save the index information read from disk. `$auto_noexec`: `$auto_noload`: `[auto_oldpath%|%$auto_oldpath]`: `[auto_path%|%$auto_path]`: `[dir%|%$dir]`: `[env%|%$env]`: `[TCL_LIBRARY%|%$env(TCL_LIBRARY)]`: `[TCLLIBPATH%|%$env(TCLLIBPATH)]`: `[errorCode%|%$errorCode]`: `[errorInfo%|%$errorInfo]`: `[tclDefaultLibrary%|%$tclDefaultLibrary]`: on unix `[tcl_interactive%|%$tcl_interactive]`: `[tcl_libpath%|%$tcl_libpath]`: `[tcl_library%|%$tcl_library]`: The name of the directory containing the scripts that compose the [Tcl Library%|%Tcl system] of the current application . Not to be confused with `[TCL_LIBRARY%|%$env(TCL_LIBRARY)]` . The initial value of this variable is determined by finding a directory that contains an appropriate Tcl startup script . Locations from the following sources are searched , in order : [TCL_LIBRARY%|%$env(TCL_LIBRARY)] , some other directories based on an internal algorithm , the location of the application executable file , and the current working directory . `[tcl_patchLevel%|%$tcl_patchLevel]`: `[tcl_pkgPath%|%$tcl_pkgPath]`: `[tcl_platform%|%$tcl_platform]`: `[tcl_precision%|%$tcl_precision]`: `[tcl_rcFileName%|%$tcl_rcFileName]`: `[tcl_rcRsrcName%|%$tcl_rcRsrcName]`: `[tcl_traceCompile%|%$tcl_traceCompile]`: `[tcl_traceExec%|%$tcl_traceExec]`: `[tcl_version%|%$tcl_version]`: `$unknown_pending`: `[tcl_wordchars%|%$tcl_wordchars]` and `[tcl_nonwordchars%|%$tcl_nonwordchars]`: There are also a number of special shell environment variables which can influence Tcl behavior. These include: [CC]: [COMSPEC]: on Windows [HOME]: [HOMEPATh%|%HOMEDRIVE]: on Windows [HOMEPATH]: on Windows [LANG]: [LC_ALL]: [LC_CTYPE]: [PATH]: [PATHEXT]: on Windows [SHLIB_CFLAGS]: [TCL_LIBRARY]: [TCLLIBPATH]: [TCLTEST_OPTIONS]: [TZ]: on Windows [windir]: on Windows <> Internals