oh, 30 bytes

Result

INVALID

Duration

945ms

Code [DL]

sed 's/.*\(.\)\(\1\| \).*/\1/'

stdin

639 882
379 946
364 443
445 451
299 792
529 272
744 446
451 265
788 884
418 618
177 268
479 491
899 919
414 213
438 285
815 335
277 765
766 227
144 598
455 953
873 775
248 447
411 776
573 334
172 583
932 239
112 185
464 437
341 346
122 779
743 341
676 763

stdout

8
9
4
5
9
9
4
1
8
8
7
9
9
4
8
3
7
2
4
5
7
4
7
3
2
2
2
4
1
7
3
6

stderr

strace

11    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffcc8396a50 /* 7 vars */) = 0
12    execve("/bin/cat", ["cat", "-"], 0x565252414048 /* 7 vars */) = 0
14    execve("/usr/bin/go", ["/usr/bin/go", "env", "GOPATH"], 0x565252414078 /* 7 vars */) = 0
12    +++ exited with 0 +++
11    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
16    +++ exited with 0 +++
17    +++ exited with 0 +++
15    +++ exited with 0 +++
18    +++ exited with 0 +++
19    +++ exited with 0 +++
14    +++ exited with 0 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
13    execve("/root/go/bin/oh", ["/root/go/bin/oh", "/volume/CODE"], 0x565252414068 /* 7 vars */) = 0
26    execve("/bin/sed", ["sed", "s/.*\\(.\\)\\(\\1\\| \\).*/\\1/"], 0xc000114b40 /* 8 vars */) = 0
26    +++ exited with 0 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=26, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
23    +++ exited with 0 +++
20    +++ exited with 0 +++
25    +++ exited with 0 +++
24    +++ exited with 0 +++
22    +++ exited with 0 +++
21    +++ exited with 0 +++
13    +++ exited with 0 +++
11    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=1, si_stime=5} ---
11    +++ exited with 0 +++