What could cause which to not show something in the path?

Question

There is an executable in my path that I believe is a perl script.

>$scriptname
$outputofscript

but

>which $scriptname
which:  0652-141 There is no $scriptname in $path

and the path it prints is the same that echo $PATH gives (except space delimited rather than colon).

Running ksh again does not appear to change my path, but now the script is not found.

This is as a normal user running ksh on AIX 6.1 over telnet (yeah, I know).

Answer 1

Running type $scriptname told me that it was an alias. Apparently this prevented it from being found by which.

Answer 2

which is a csh script on AIX, and it might use a different path. But that doesn't seem to be exactly your problem, since which prints the expected path.

Are you absolutely sure you didn't have a different path in the first ksh session? Running ksh again might have changed the PATH because it ran ~/.kshrc or $ENV. (And just to be sure, does the script still exist, or could it simply have been deleted in the meantime?)