fish-shell-pure, 90 bytes

Result

AC

Duration

846ms

Code [DL]

while read -n1 _
read -n1 b
read -n1 c
read -n2 d
read _
[ $b = $c ]&&echo $b||echo $d
end

stdin

683 946
956 383
733 449
813 318
696 171
383 446
388 776
311 745
523 926
765 562
998 885
339 196
286 374
789 846
955 354
211 244
415 651
377 478
277 718
822 224
271 711
852 512
561 563
634 447
855 578
155 558
223 226
424 477
718 185
761 338
162 215
516 118

stdout

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

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc90919c30 /* 9 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x5633e0b8ad18 /* 9 vars */) = 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} ---
12    execve("/bin/cp", ["cp", "-f", "/volume/CODE", "/opt/jails/fish-shell-pure/code."...], 0x5633e0b8ad68 /* 9 vars */) = 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=0, si_stime=0} ---
13    execve("/bin/cat", ["cat", "-"], 0x5633e29630e0 /* 9 vars */) = 0
14    execve("/usr/sbin/jk_chrootlaunch", ["jk_chrootlaunch", "-j", "/opt/jails/fish-shell-pure", "-x", "/bin/fish", "/code.fish"], 0x5633e29631b0 /* 9 vars */) = 0
13    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
14    execve("/bin/fish", ["/bin/fish", "/code.fish"], 0x7fff66e845a0 /* 9 vars */) = 0
14    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=1, si_stime=1} ---
15    execve("/bin/rm", ["rm", "/opt/jails/fish-shell-pure/code."...], 0x5633e0b8acc8 /* 9 vars */) = 0
15    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=15, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++