Docco

[Phi Debian]

$ man bash
...
CONDITIONAL EXPRESSIONS
...

       -a file
              True if file exists.
       -e file
              True if file exists.
...

'May be' would be nice for newbies to precise which options are [ specific
vs [[ specific for instance

       -a file
              True if file exists ([[ only, for [ see test builtin)

This to avoid things like

$ [   -a /tmp ] && echo ok || echo nok
ok
$ [ ! -a /tmp ] && echo ok || echo nok
ok

I know it is obvious, unless this is intended to force a complete
multi-pass man read...