> [ ] is a command—basically another way to call the built-in test command. Literally, '/usr/bin/[', which takes as an argument a final ']', but actually a dif

> [ ] is a command—basically another way to call the built-in test command. Literally, '/usr/bin/[', which takes as an argument a final ']', but actually a different binary than '/usr/bin/test'. And is different from the bash builtin. Crazy shit. vagrant@vagrant:~$ [ --version -bash: [: missing `]' vagrant@vagrant:~$ /usr/bin/[ --version [ (GNU coreutils) 8.28 Copyright (C) 2017 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by Kevin Braunsdorf and Matthew Bradburn.