Created attachment 465 [details]
a code to reporduce the problem

Dear geant4 developpers,

A crash is occurred at the line 154 in G4VBasicShell.cc,
L154  : if(newPath(newPath.size()-3,3) == "/..") {


When newPath is "/", newPath.size()-3 is negative,
and a software is crashed with the following message.

terminate called after throwing an instance of 'std::out_of_range'
  what():  basic_string::substr: __pos (which is 18446744073709551614) > this->size() (which is 1)
Aborted (core dumped)

The actual situation in my application is as follows.
When "ls" is issued in the UIterminal interface, 
the following functions are called and finally crashed. 
G4UIterminal::GetCommand
G4VBasicShell::ListDirectories
G4VBasicShell::FindDirectory
G4VBasicShell::ModifyPath

The same thing is reproduced with the attached code.

Best regards,
Hajime