To be honest i don't see how this is supposed to be "cool". "Wicked" yes, but cool?

I'd write it this way and you will understand why once you have scripts several thousand lines long to maintain. If this is meant for bash instead of ksh replace "typeset" with "local":

Code:

in_path()
{
typeset    chCmd="$1"                # command
typeset    fOurPath="$2"             # list of colon-separated dirs
typeset    fDir=""                   # single directory buffer

$chFullDebug

echo "$fOurPath" |\
while IFS=":" read fDir ; do
     if [ -x "${fDir}/${chCmd}" ] ; then
          return 0
     fi
done

return 1
}

A few things to notice:

Variables can change their content easily in shell scripts. Strings can become numbers and vice versa. To maintain a modicum of runtime security i always use qualifiers (see "Hungarian Style Notation") to denote the "type" of a variable. This helps me to keep track in complicated and long scripts. I use:

f... = "file", a filename, directory or generally a path
i... = "int", an integer number
ch.. = "char", a string
l... = "logical", basically an int, but i use only values 0 and 1

It doesn't matter what system you use as long as you stay consistently with it. You do not need to adopt my system, but you should have some system, otherwise you will create a mess over time.

Second: i have declared all my variables i use in the function. This not only encapsulates the function (there is no danger with side effects) but i can also document what i use the variables for and what they should contain. If something goes wrong i can display what is in the variables and compare that with the the mini-data-dictionary at the top of the function.

Third: when the test for an executable is positive there is no point in testing the rest of the path. Therefore i leave the loop immediately via the return-statement in this case.

Fourth: using the while-loop i can specify a custom IFS for the single read-command, so i do not need to save and restore the IFS.

Fifth: all the strings are protected by double-quotes always. This increases run-time security because this way i never have to worry about strings containing white space.

And finally: you notice the line $chFullDebug. This variable is nowhere defined or used in the function. It is a global which i set in my scripts. Under normal conditions the variable is an empty string and the line does nothing. If i need to fully debug a script i set this to set -xv because setting these shell options in the main program would have them switched off with every entering of a subfunction. This way, by writing it into every function i can globally switch debugging on or off.

I hope this helps.

bakunin