Installation-Related Programs user = unix_user4 comp_err [ options ] 395 The name of the error header file. The default is  mysqld_error.h . The name of the error message file. The default is  mysqld_errmsg.h . This option was added in MySQL 8.0.18. Print some debugging information when the program exits. Write a debugging log. A typical  debug_options  string is  d:t:O, file_name . The default is  d:t:O,/ tmp/comp_err.trace . The character set directory. The default is  ../sql/share/charsets . Display a help message and exit. comp_err  supports the following options. Invoke  comp_err  like this: comp_err  also generates the  mysqld_error.h ,  mysqld_ername.h , and  mysqld_errmsg.h  header files. For more information about defining error messages, see the comments within those files, along with the errmsg_readme.txt  file. comp_err  creates the  errmsg.sys  file that is used by  mysqld  to determine the error messages to display for different error codes.  comp_err  normally is run automatically when MySQL is built. It compiles the  errmsg.sys  file from text-format error information in MySQL source distributions: The programs in this section are used when installing or upgrading MySQL. See Section 4.2.2.2, “Using Option Files” . 4.4 Installation-Related Programs 4.4.1 comp_err — Compile MySQL Error Message File • --header-file= file_name ,  -H  file_name • --errmsg-file= file_name ,  -H  file_name • --debug-info ,  -T • --debug= debug_options ,  -#  debug_options • --charset= dir_name ,  -C  dir_name • --help ,  -? •Prior to MySQL 8.0.19, the error information comes from the  errmsg-utf8.txt  file in the  sql/share directory. •As of MySQL 8.0.19, the error information comes from the  messages_to_error_log.txt  and messages_to_clients.txt  files in the  share  directory.