The '''main script''' is the primary script that is executed by the interpreter
, e.g. [tclsh] or [wish] .



** Description **

One common technique is to have a script run a self test if it detects that it
is the main script .  The detection routine usually looks something like this: 

======
if {[info exists argv0] && $argv0 eq [info script]} {
    #do stuff
}
======

or , as formulated in a [comp.lang.tcl] posting by [DKF]:

======
if {[string equal $::argv0 [info script]] || [
    array exists ::embed_args]} {
    main
} 
======

Examples of the following more complicated test can be found :

======
#unneeded complexity ?
if {[info exists argv0] && [file tail [info script]] eq [file tail $argv0]} {
    #do stuff
}
======

but I ([PYK]) don't see a scenario in which is needed , as `[info script]`
always has the same value as `$[argv0]` in all the cases I tested .