• Eric Blake's avatar
    tests: Avoid non-portable 'echo -ARG' · b43671f8
    Eric Blake authored
    POSIX says that backslashes in the arguments to 'echo', as well as
    any use of 'echo -n' and 'echo -e', are non-portable; it recommends
    people should favor 'printf' instead.  This is definitely true where
    we do not control which shell is running (such as in makefile snippets
    or in documentation examples).  But even for scripts where we
    require bash (and therefore, where echo does what we want by default),
    it is still possible to use 'shopt -s xpg_echo' to change bash's
    behavior of echo.  And setting a good example never hurts when we are
    not sure if a snippet will be copied from a bash-only script to a
    general shell script (although I don't change the use of non-portable
    \e for ESC when we know the running shell is bash).
    
    Replace 'echo -n "..."' with 'printf %s "..."', and 'echo -e "..."'
    with 'printf %b "...\n"', with the optimization that the %s/%b
    argument can be omitted if the string being printed is a strict
    literal with no '%', '$', or '`' (we could technically also make
    this optimization when there are $ or `` substitutions but where
    we can prove their results will not be problematic, but proving
    that such substitutions are safe makes the patch less trivial
    compared to just being consistent).
    
    In the qemu-iotests check script, fix unusual shell quoting
    that would result in word-splitting if 'date' outputs a space.
    
    In test 051, take an opportunity to shorten the line.
    
    In test 068, get rid of a pointless second invocation of bash.
    
    CC: qemu-trivial@nongnu.org
    Signed-off-by: 's avatarEric Blake <eblake@redhat.com>
    Message-id: 20170703180950.9895-1-eblake@redhat.com
    Signed-off-by: 's avatarMax Reitz <mreitz@redhat.com>
    b43671f8
qemu-options.hx 172 KB