Fix documentation for new redirection operators

[stevengj]

In commit 377de75, the redirection operators were renamed to |>, but the documentation was not updated accordingly.

I'm not really clear on the reason for the rename; I can't find any discussion of this, which seems odd for a patch that breaks major features. Why wasn't there an RFC pull request?

@StefanKarpinski's blog post on pipes and shells should also be updated at some point.

@loladiro?

[Keno]

The main reason for this change was to clarify the meaning of generic operators and to avoid using the same operator for many different purposes. In bash this isn't really an issue as you can't really do an or and a pipe redirect in the same statement, but in Julia that might very well happen. Another reason was to replace > as the file redirect operator, since that conflicted with a>b>c (which gets parsed as a>b&&b>c) and let to weird results.

We discussed this offline and prior to that there was also some discussion in one of the issues (though I forget which one), which probably explains the absence of an RFC PR. You are right, the documentation does need to be updated. In general, we need to do a documentation sprint before the 0.2 release.

[pao]

Related is #3270.

[nolta]

JuliaLang/www_old.julialang.org#33