I don't imagine that there are many Tcl jobs listed. The posting said that Joe is a Tcl/Tk maintainer; presumably why he puts this on his CV is not because of

I don't imagine that there are many Tcl jobs listed. The posting said that Joe is a Tcl/Tk maintainer; presumably why he puts this on his CV is not because of Tcl's current market share, but because being a maintainer for a historically widespread language reveals a skill set. If you ever thought of embedding Lua into something, Tcl isn't a bad alternative.