Stupid little shell puzzle

From: Shawn Bayern (shawn.bayern@yale.edu)
Date: Sat Sep 11 1999 - 13:32:42 EDT


This actually came up when my department was trying to solve a problem the
other day; I figured it might be slightly interesting. :)

In most Unix shells, $$ is supposed to return the pid of the current
process. () produces subshells. So why does the following little script
return the same two values --

        #!/bin/sh
        echo $$
        (echo $$)

-- and, since the "obvious" thing doesn't work, what are the possible
workarounds if you want to get the pid of a subshell?

The answer made me laugh, but then again, I have a weird sense of humor. ;)

Shawn



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