The GDB command file lets you choose with program to debug.
(gdbslet) file prog
GDB then attempts to read the symbol table of prog.
GDB locates
the file by searching the directories listed in the command search
path.
If the file was compiled with debug information (option "-g"), source
files will be searched as well.
GDB locates
the source files by searching the directories listed in the directory search
path (see Your program's environment).
If it fails
to find a file, it displays a message such as:
prog: No such file or directory.
When this happens, add the appropriate directories to the search paths with
the GDB commands path and dir, and execute the
target command again.