Tools to check file size, file/directory existence

[demyan]

I would be great to have a tool to check:

• file size
• file exist
• directory exist

KDB has hcount and key:
https://code.kx.com/q/ref/hcount/
https://code.kx.com/q/ref/key/#whether-a-file-exists

q)hcount `:exist
0
q)hcount `:nonexist
'nonexist. OS reports: No such file or directory
  [0]  hcount `:nonexist
       ^
q)hcount `:existDir
'existDir. OS reports: Is a directory
  [0]  hcount `:existDir
       ^

q)key `:exist
`:exist
q)key `:existDir
,`1
q)key `:existEmptyDir
`symbol$()
q)key `:nonexist
q)type key `:nonexist
0h