d-gdc, 72 bytes

Result

WA

Duration

921ms

Code [DL]

import std.stdio;void main(){readln(s)&&putchar=s[s[1]-s[2]?4:1]&&main;}

stdin

824 245
821 215
255 586
893 986
737 748
163 882
967 621
355 456
822 221
639 992
599 699
936 483
366 711
383 459
544 487
448 667
139 436
393 338
211 951
478 776
184 649
369 912
126 461
228 126
921 273
465 379
699 228
477 773
327 727
251 559
911 334
389 989

stdout

stderr

/tmp/code.d:1:37: error: undefined identifier 's'
 import std.stdio;void main(){readln(s)&&putchar=s[s[1]-s[2]?4:1]&&main;}
                                     ^
/tmp/code.d:1:41: error: function core.stdc.stdio.putchar (int c) is not callable using argument types ()
 import std.stdio;void main(){readln(s)&&putchar=s[s[1]-s[2]?4:1]&&main;}
                                         ^
/root/script: 7: /root/script: /tmp/code: not found
rm: cannot remove '/tmp/code': No such file or directory

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffdbc35e8a0 /* 6 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55c665045c00 /* 6 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/ln", ["ln", "-sf", "/volume/CODE", "/tmp/code.d"], 0x55c665045c20 /* 6 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("/usr/bin/gdc", ["gdc", "/tmp/code.d", "-o", "/tmp/code"], 0x55c665045c18 /* 6 vars */) = 0
14    execve("/usr/lib/gcc/x86_64-linux-gnu/8/cc1d", ["/usr/lib/gcc/x86_64-linux-gnu/8/"..., "/tmp/code.d", "-quiet", "-dumpbase", "code.d", "-mtune=generic", "-march=x86-64", "-auxbase", "code", "-imultiarch", "x86_64-linux-gnu", "-o", "/tmp/cc6YevxO.s"], 0x15a85e0 /* 11 vars */) = 0
14    +++ exited with 1 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=1, si_utime=5, si_stime=2} ---
13    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=1, si_utime=0, si_stime=0} ---
15    execve("/bin/cat", ["cat", "-"], 0x55c665045be8 /* 6 vars */ <unfinished ...>
16    execve("/tmp/code", ["/tmp/code"], 0x55c665045bd0 /* 6 vars */) = -1 ENOENT (No such file or directory)
15    <... execve resumed> )            = 0
16    +++ exited with 127 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=16, si_uid=0, si_status=127, si_utime=0, si_stime=0} ---
15    --- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=15, si_uid=0} ---
15    +++ killed by SIGPIPE +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_KILLED, si_pid=15, si_uid=0, si_status=SIGPIPE, si_utime=0, si_stime=0} ---
17    execve("/bin/rm", ["rm", "/tmp/code.d", "/tmp/code"], 0x55c665045bd0 /* 6 vars */) = 0
17    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=17, si_uid=0, si_status=1, si_utime=0, si_stime=0} ---
10    +++ exited with 1 +++