#0  0x00007fce4bf4da37 in __GI___libc_write (fd=1, buf=0x556021b5e710, nbytes=6) at ../sysdeps/unix/sysv/linux/write.c:26
#1  0x00007fce4bec3f6d in _IO_new_file_write (f=0x7fce4c053780 <_IO_2_1_stdout_>, data=0x556021b5e710, n=6) at ./libio/fileops.c:1180
#2  0x00007fce4bec5a61 in new_do_write (to_do=6, data=0x556021b5e710 "error\n", fp=0x7fce4c053780 <_IO_2_1_stdout_>)
    at ./libio/libioP.h:947
#3  _IO_new_do_write (to_do=6, data=0x556021b5e710 "error\n", fp=0x7fce4c053780 <_IO_2_1_stdout_>) at ./libio/fileops.c:425
#4  _IO_new_do_write (fp=fp@entry=0x7fce4c053780 <_IO_2_1_stdout_>, data=0x556021b5e710 "error\n", to_do=6) at ./libio/fileops.c:422
#5  0x00007fce4bec5f43 in _IO_new_file_overflow (f=0x7fce4c053780 <_IO_2_1_stdout_>, ch=10) at ./libio/fileops.c:783
#6  0x000055601fb0c5f9 in echo_builtin ()
#7  0x000055601fab592c in ?? ()
#8  0x000055601faae653 in ?? ()
#9  0x000055601faafafd in execute_command_internal ()
#10 0x000055601fab2158 in execute_command ()
#11 0x000055601fab0244 in execute_command_internal ()
#12 0x000055601fab2158 in execute_command ()
#13 0x000055601faa338b in reader_loop ()
#14 0x000055601fa94c06 in main ()