I finally learn how to do realpath

Kevin Fenzi said I should send my shell-level realpath off to the maintainer of an appropriate package -- coreutils, maybe -- for possible inclusion.

So, I wrote unit tests, a simple Makefile and documentation: man page, README, INSTALL, stuff like that.

Kevin, wiser than I, looked and found documentation that suggested readlink -f would do the trick. And it does. I could prove it to myself because I had unit tests.

One difference in functionality, which I can live with: if the file is missing, readlink -f succeeds and reports it's in the current directory.

So, to find the path to an executable, this does the trick:

path2 () {
local _cmd=$(type -p $1)
[ -f $_cmd ] && readlink -f $_cmd
}