m4, 68 bytes

Result

AC

Duration

851ms

Code [DL]

syscmd(awk '$1{for($0=$0t;sub(/K /,"KK");)sub(/ {50}/,z);t=$0}$0=t')

stdin

                                   T              
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
          K                                       

stdout

                                   T              
                                   T              
                                   T              
                                   T              
                                   T              
                                   T              
                                   T              
                                   T              
                                   T              
          KKKKKKKKKKKKKKKKKKKKKKKKKT              

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffdc878a100 /* 7 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x56302edc8d30 /* 7 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("/usr/bin/m4", ["/usr/bin/m4", "/volume/CODE"], 0x56302edc8d40 /* 7 vars */) = 0
13    execve("/bin/sh", ["sh", "-c", "awk '$1{for($0=$0t;sub(/K /,\"KK\""...], 0x7ffdccd5aaa0 /* 7 vars */) = 0
13    execve("/usr/bin/awk", ["awk", "$1{for($0=$0t;sub(/K /,\"KK\");)su"...], 0x562efbcd4d38 /* 7 vars */) = 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=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} ---
10    +++ exited with 0 +++