How to get the pathname of the current executable?

[Jim Kohli]

In article <5378 at buengc.BU.EDU>, bph at buengc.bu.edu (Blair P. Houghton) writes:
<In article <1990Feb7.211538.3894 at iwarp.intel.com> merlyn at iwarp.intel.com (Randal Schwartz) writes:
<>In article <1610.25d028a3 at wums.wustl.edu>, bethge at wums writes:
<>[wants to know how to find the name of the current executable]
<>| Is there a better (more transparent) way?
<>
<>No.  This was hashed out about a year ago in either c.u.q or c.u.w.
<>Basically, it boils down to the fact that you have no idea where you
<>came from, and the closest you could come is to count on the shells to
<>*mostly* give you the right answer *most* of the time in argv[0].
<>However, programs that do execv() are free to provide *whatever* they
<>want.  So, you're out of luck, and subject to spoofing.
<>
<>Just another UNIX hacker,
<
<Sum hecker.
<
<Take argv[0], if it doesn't have the path, or the full path,
<cut it up to get the command name, say "prog", then strcat(3)
<it onto "/usr/ucb/which" and call system(3):
<
<    foo = "/usr/ucb/which prog"
<    system(foo);
<
<As long as you're still in the directory from which the
<program was run, and as long as your path was the same
<as the one set in your .cshrc (someone please tell me
                                ^^^^^^^^^^^^^^^^^^^^^^
<why which(1) reads the .cshrc...) then you'll come up
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
<with /usr/foo/bar/bletch/prog, barring surreptition.
<
<[...the rest of Blair's fine response excised...]
<
reading .cshrc may be somewhat helpful in resolving
aliases, eh?  although this doesn't help, as you said,
for cases where the path gets munged at the same time.

jim kohli
ge medical systems