▁ ▁All ▁commands ▁defined ▁by ▁T cl ▁itself ▁generate ▁error ▁messages ▁on ▁incorrect ▁usage . ▁ ▁Ext ens ibility , ▁via ▁C , ▁C ++, ▁Java , ▁Python , ▁and ▁T cl . ▁ ▁Inter pre ted ▁language ▁using ▁byte code ▁ ▁Full ▁Unicode ▁( 3 . 1 ▁in ▁the ▁beginning , ▁regularly ▁updated ) ▁support , ▁first ▁released ▁ 1 9 9 9 . ▁ ▁Reg ular ▁expressions ▁ ▁Cross - platform : ▁Windows ▁API ; ▁Unix , ▁Linux , ▁Mac int osh ▁etc . ▁ ▁Close , ▁cross - platform ▁integration ▁with ▁window ing ▁( G UI ) ▁interface ▁T k . ▁ ▁Multiple ▁distribution ▁mechan isms ▁exist : ▁ ▁Full ▁development ▁version ▁( for ▁Windows ▁e . g . ▁Active State ▁T cl , ▁see ▁) ▁ ▁T clk its ▁( single ▁file ▁executable ▁containing ▁a ▁complete ▁script ing ▁runtime , ▁only ▁about ▁ 4 ▁meg aby tes ▁in ▁size ), ▁St ark its ▁( w ra pping ▁mechanism ▁for ▁deliver ing ▁an ▁application ▁in ▁a ▁self - cont ained , ▁installation - free , ▁and ▁highly ▁port able ▁way ) ▁and ▁Star pack s ▁( comb ine ▁St ark it ▁with ▁T cl kit ▁to ▁produce ▁a ▁Star pack ▁- ▁a ▁single ▁platform ▁specific ▁executable ▁file , ▁ideal ▁for ▁easy ▁deployment ) ▁ ▁The ▁Jim ▁Inter pre ter , ▁a ▁small ▁foot print ▁T cl ▁implementation ▁ ▁Fre ely ▁distrib utable ▁source ▁code ▁under ▁a ▁B SD ▁license . ▁ ▁Sa fe - T cl ▁ ▁Sa fe -