The error message " ⎕SE.Link.Create: File name case clash - try using caseCode←1:" is unhelpful to a newbie

[dyaandys]

On macOS I created foo, Foo and FOO, and then tried
]link.Create #
ERRORS ENCOUNTERED: ⎕SE.Link.Create: File name case clash - try using caseCode←1:
#.FOO
#.Foo
#.FOO
#.foo

1. Why does FOO appear twice ?
2. I needed Morten to help me get to
   ]link.Create # -casecode
   .. I went via
   ]link.Create # -caseCode=1

• Command Execution Failed: unknown modifier: "caseCode"
  ]link.Create # -casecode=1
• Command Execution Failed: no value allowed for modifier

Can the error be more command line centric please ?

Dyalog 19.0.48774 64-bit Unicode, BuildID 2b135e73
OS Darwin 22.4.0 Darwin Kernel Version 22.4.0: Mon Mar 6 21:00:41 PST 2023; root:xnu-8796.101
Link 4.0.13
SALT 2.915
UCMD 2.6
.NET .NET 8.0.1
WS 19.0