Re: here-documents in $(command) substitution

[Eduardo Bustamante]

Hi Alexey,

Please read the specification of here-documents in the standard:
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_07_04

Quoting the relevant parts:

    The here-document shall be treated as a single word that begins
after the next <newline> and continues until there is a line
containing only the delimiter and a <newline>, with no <blank>
characters in between. Then the next here-document starts, if there is
one. [...]

    [n]<<word
        here-document
    delimiter

Delimiter (in your case the three character string "EOF"), has to be
on its own line, with no leading or trailing blanks (or any other
characters). If bash 3.x used to behave different, it's because it was
buggy.

Hence, the proper way to do a here-document inside command substitution:

    hp% cat hd
    export foo=$(cat <<EOF
    echo bar
    EOF
    )
    echo baz
    hp% bash hd
    baz