Definitely quote. `[ x$X == x"hello" ]` may fail for a variety of different valu...

naniwaduni · on April 13, 2021

Of the listed, it should only actually fail on the ones with spaces in them (or rather, the ones that get split according to IFS).

koala_man · on April 13, 2021

Whether or not it should, it may fail for any kind of glob.

This could be either because the glob ends up unintentionally matching something:

    $ var='*'; touch xfoo xbar
    $ [ x$var == x"hello" ]
    bash: [: too many arguments

    $ var="Rocky_[1976].jpg"; touch xRocky_7.jpg
    $ [ x$var == x"Rocky_[1976].jpg" ]
    (false, should be true)

or because you have something like nullglob or failglob enabled:

    $ var="Rocky_[1976].jpg"; shopt -s nullglob
    $ [ x$var == x"hello" ]
    bash: [: ==: unary operator expected