A utility script which should, in theory, locate the main function of a stripped x86 32-bit or 64-bit elf binary.
(gdb) source ./entry.py
Program stopped.
0x00007ffff7fd4100 in _start () from /lib64/ld-linux-x86-64.so.2
Breakpoint 1 at 0x555555555050
Breakpoint 1, 0x0000555555555050 in _start ()
0x0000555555555054 in _start ()
0x0000555555555056 in _start ()
0x0000555555555059 in _start ()
0x000055555555505a in _start ()
0x000055555555505d in _start ()
0x0000555555555061 in _start ()
0x0000555555555062 in _start ()
0x0000555555555063 in _start ()
0x000055555555506a in _start ()
0x0000555555555071 in _start ()
0x0000555555555078 in _start ()
Breakpoint 2 at 0x555555555149
Breakpoint 2, 0x0000555555555149 in main ()
main @ 0x555555555149
(gdb) x/20i $rip
=> 0x555555555149 <main>: push rbp
0x55555555514a <main+1>: mov rbp,rsp
0x55555555514d <main+4>: sub rsp,0x20