auto_execok is one of several ''commands'' documented at http://www.tcl.tk/man/tcl8.4/TclCmd/library.htm ---- Canonical example usage: eval exec [auto_execok dir] *.$suffix [[Explain why this is better than $::env(COMSPEC), cmd.exe, ...]] ---- To demonstrate why [[eval]] is required: % auto_execok start C:/WINNT/system32/CMD.EXE /c start % exec [auto_execok start] http://wiki.tcl.tk couldn't execute "C:\WINNT\system32\CMD.EXE \c start": invalid argument % eval exec [auto_execok start] http://wiki.tcl.tk % # success ---- See also [exec], [Invoking browsers], ---- [Tcl syntax help] - [Arts and crafts of Tcl-Tk programming] - [Category Command]