perl6, 51 bytes

Result

AC

Duration

1496ms

Code [DL]

($=$_~|($||=$_))~~{1 while s/k\s/kk/;.say}for lines

stdin

               T                                  
                                                  
                                                  
      K                                           

stdout

               T                                  
               t                                  
               t                                  
      kkkkkkkkkt                                  

stderr

WARNINGS for /volume/CODE:
Useless use of constant integer 1 in sink context (use Nil instead to suppress this warning) (line 1)

strace

11    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffc63451ba0 /* 7 vars */) = 0
12    execve("/bin/cat", ["cat", "-"], 0x55df2fa9dd30 /* 7 vars */ <unfinished ...>
13    execve("/usr/bin/perl6", ["/usr/bin/perl6", "/volume/CODE"], 0x55df2fa9dd40 /* 7 vars */ <unfinished ...>
12    <... execve resumed> )            = 0
13    <... execve resumed> )            = 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} ---
13    execve("/usr/bin/moar", ["/usr/bin/moar", "--execname=/usr/bin/perl6", "--libpath=/usr/share/nqp/lib", "--libpath=/usr/share/nqp/lib", "--libpath=/usr/share/perl6/lib", "--libpath=/usr/share/perl6/runti"..., "/usr/share/perl6/runtime/perl6.m"..., "/volume/CODE"], 0x558fa3fd30c0 /* 7 vars */) = 0
14    +++ 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=37, si_stime=13} ---
11    +++ exited with 0 +++