http://www.purl.org/tcl/home/man/tcl8.4/TclCmd/scan.htm
display and numeric format for ASCII characters. display and numeric format for ASCII characters. Scan provides the usual answer:
foreach character {a A b B c} {
scan $character %c numeric
puts "ASCII character '$numeric' displays as '$character'."
}
ASCII character '97' displays as 'a'.
ASCII character '65' displays as 'A'.
ASCII character '98' displays as 'b'.
ASCII character '66' displays as 'B'.
ASCII character '99' displays as 'c'.
Also see "Dump a file in hex and ASCII", as well as "u2x" in the "Bag of algorithms".
Tcl syntax help - Arts and crafts of Tcl-Tk programming - Category Command