The task is to programmatically obtain the name used to invoke the program. (For example determine whether the user ran "python hello.py", or "python hellocaller.py", a program importing the code from "hello.py".)

Sometimes a multiline shebang is necessary in order to provide the script name to a language's internal ARGV.

See also Command-line arguments

Examples from GitHub.

#!/usr/bin/env tclsh
 
proc main {args} {
    set program $::argv0
    puts "Program: $program"
}
 
if {$::argv0 eq [info script]} {
    main {*}$::argv
}