oh, 30 bytes

Result

INVALID

Duration

1144ms

Code [DL]

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

stdin

963 432
799 995
199 912
178 773
423 149
756 739
629 187
112 614
718 881
299 915
993 363
652 834
454 451
522 322
647 427
653 115
825 255
991 177
722 775
769 664
842 925
751 543
199 997
866 429
646 466
533 415
774 441
689 225
924 423
197 397
677 338
611 812

stdout

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

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffecb958160 /* 7 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x55c813091048 /* 7 vars */ <unfinished ...>
13    execve("/usr/bin/go", ["/usr/bin/go", "env", "GOPATH"], 0x55c813091078 /* 7 vars */ <unfinished ...>
11    <... execve resumed>)             = 0
13    <... execve resumed>)             = 0
11    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=11, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
17    +++ exited with 0 +++
16    +++ exited with 0 +++
15    +++ exited with 0 +++
14    +++ exited with 0 +++
13    +++ exited with 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
12    execve("/root/go/bin/oh", ["/root/go/bin/oh", "/volume/CODE"], 0x55c813091068 /* 7 vars */) = 0
24    execve("/bin/sed", ["sed", "s/.*\\(.\\)\\(\\1\\| \\).*/\\1/"], 0xc000164be0 /* 8 vars */) = 0
24    +++ exited with 0 +++
12    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=24, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
23    +++ exited with 0 +++
22    +++ exited with 0 +++
19    +++ exited with 0 +++
18    +++ exited with 0 +++
20    +++ exited with 0 +++
21    +++ exited with 0 +++
12    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=2, si_stime=4} ---
10    +++ exited with 0 +++