1. To build C/C++ codes including zlib.h, gcc flag "-lz" must be added, such as gcc -o kseq -lz kseq.h kseq_test.c
2. To check if some file/dir is affected by SELinux, use command "ls -Z xxx".
3. To change the security context in Linux, run command like "chcon -R -h -t httpd_sys_content_t /var/www/html/wordpress".
4. To start/stop/restart Apache, execute "apachectl start/stop/restart".
5. To admin MySQL, use "mysqladmin -u <user> -p <cmd>", such as "mysqladmin -uroot -p ping".
6. To start MySQL as root, you can "mysql -uroot -p".
7. To detect memory leakage of C/C++, using tool Valgrind and execute “valgrind --leak-check=yes myprog arg1 arg2 “.
   
8. To include AMS Math package in your LaTeX file, include the following in the preamble of your document:

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}