Richard Suchenwirth will have to exercise Tcl with colleagues who are familiar with the Bourne shell (/bin/sh - see Tcl heritage for the influences it had on Tcl!), and one task will be to prelace /bin/sh scripts with equivalent Tcl scripts.
To make this migration easier, I am planning to introduce some syntactic sugar (Salt and sugar), so familiar built-ins can still be used. Most simply with interp alias:
interp alias {} echo {} puts stdout
interp alias {} read {} gets stdinNote however that echo's output cannot be redirected to a file, or through a pipe. Things like
foo=`echo $bar | grep "^grill"`
would have to be restructured:
set foo [exec grep ^grill <<$bar]
which also has its charms, but needs habituation. (On the other hand, a Tcl'er would prefer regexp anyway...)
Another difference is the exit status - if grep can't find a thing, it still raises no direct error in /bin/sh, but you can check the exit status with the special variable $? afterwards.
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Tcl and other languages - Arts and crafts of Tcl-Tk programming