On 5/24/16 1:41 AM, Dan Douglas wrote: >> You don't precede it with an `exec', so it doesn't affect the current >> shell. So-called `null' commands with redirections are executed in >> subshells. This is where you need the `exec'. > > I know POSIX allows for a subshell but don't know what the point is. I > was confused by this when I first hit it. The subshell isn't obvious.
It's not that Posix `allows' a subshell, it requires a subshell environment: "If there is no command name, any redirections shall be performed in a subshell environment." Bash produces a subshell environment by creating a subshell. -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/