[http://www.tcl.tk/man/tcl/UserCmd/tclsh.htm#M10|%|%tclsh man page%|%]

This global variable identifies whether the tcl interpreter is operating in
interactive mode or not.  If its value is 1 , then the interpreter acts as if
it were an interactive interpreter. See [tclsh] for a list of the differences
between interactive and non-interactive mode.

[Ro]: You can shorten commands in interactive mode, e.g.: "inf" for "info".

[RS] 2004-03-24: Yup - and this is especially delightful on a [PocketPC] where
less stylus-tapping is better. If the abbreviation is unambiguous, like ''ll''
for [[[llength]], it saves time and screen space; if it is ambiguous (e.g.
'l'), it is another [introspection] helper - the educational error message
shows you the possible completions, just as [[info command l*]] would have
done. 

======none
% l
ambiguous command name "l": label labelframe lappend lindex linsert list listbox
llength load loadvfs lower lrange lreplace lsearch lset lsort
% ll
wrong # args: should be "llength list"
======

Just make sure that the interactive command is tried at global level (0), so that [unknown] (which provides abbreviation mode) finds itself at level 1.

----
If [tclsh] runs a script given on the command line, [tcl_interactive] is set to 0, but adding the line

======
set ::tcl_interactive 1
======

gives you the described benefits, so I added that to [iFile 1.1].

[DGP]: Note this feature is new in Tcl 8.4.  Note also that the intended user
of this feature is Tcl's test suite.  Use with care.

[JMN] 2008: This variable seems to be undefined in new threads created using the Thread package.
I suspect this is a bug, as other variables such as tcl_patchLevel do exist in new threads.
On loading a module into another thread, which uses ::tcl_patchLevel to change its logging behaviour slightly, I get the error:

======none
can't read "::tcl_interactive": no such variable
======


<<categories>> Tcl syntax | Internals