Re: [Help-bash] How to let a command take multiple here-doc?

[Eric Blake]

On 05/29/2015 06:29 AM, Eric Blake wrote:

> 
> On systems with /dev/fd, you can do:

Bash documents that it special-cases /dev/fd/n as the target of a
redirection operator, but that is different than my usage here.

> 
> $ cat - /dev/fd/4 <<EOF 4<<EOF
>> a
>> EOF
>> b
>> EOF
> a
> b
> 
> for a single cat process that reads from two different fds.  But it's
> such an unusual idiom that I don't recommend it for code trying to be
> portable.

Meanwhile, this points out a bug in 'man bash'.  Whereas for most
redirections, the manual lists the optional '[n]' for the default fd of
0 or 1, the heredoc redirection fails to mention [n]:

       The general format for redirecting input is:
              [n]<word

       The general format for redirecting output is:
              [n]>word

       The general format for appending output is:
              [n]>>word

       The format of here-documents is:
              <<[-]word
                      here-document
              delimiter

It should be "[n]<<[-]word".

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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