Setting Environment Variables •The  mysql.slave_master_info  system table has  Master_compression_algorithms  and Master_zstd_compression_level  columns. If the  master.info  file exists, it contains lines for those values as well. 4.2.9 Setting Environment Variables Environment variables can be set at the command prompt to affect the current invocation of your command processor, or set permanently to affect future invocations. To set a variable permanently, you can set it in a startup file or by using the interface provided by your system for this purpose. Consult the documentation for your command interpreter for specific details. Section 4.9, “Environment Variables” , lists all environment variables that affect MySQL program operation. To specify a value for an environment variable, use the syntax appropriate for your command processor. For example, on Windows, you can set the  USER  variable to specify your MySQL account name. To do so, use this syntax: SET USER= your_name The syntax on Unix depends on your shell. Suppose that you want to specify the TCP/IP port number using the  MYSQL_TCP_PORT  variable. Typical syntax (such as for  sh ,  ksh ,  bash ,  zsh , and so on) is as follows: MYSQL_TCP_PORT=3306 export MYSQL_TCP_PORT The first command sets the variable, and the  export  command exports the variable to the shell environment so that its value becomes accessible to MySQL and other processes. For  csh  and  tcsh , use  setenv  to make the shell variable available to the environment: setenv MYSQL_TCP_PORT 3306 The commands to set environment variables can be executed at your command prompt to take effect immediately, but the settings persist only until you log out. To have the settings take effect each time you log in, use the interface provided by your system or place the appropriate command or commands in a startup file that your command interpreter reads each time it starts. On Windows, you can set environment variables using the System Control Panel (under Advanced). On Unix, typical shell startup files are  .bashrc  or  .bash_profile  for  bash , or  .tcshrc  for  tcsh . Suppose that your MySQL programs are installed in  /usr/local/mysql/bin  and that you want to make it easy to invoke these programs. To do this, set the value of the  PATH  environment variable to include that directory. For example, if your shell is  bash , add the following line to your  .bashrc  file: PATH=${PATH}:/usr/local/mysql/bin bash  uses different startup files for login and nonlogin shells, so you might want to add the setting to .bashrc  for login shells and to  .bash_profile  for nonlogin shells to make sure that  PATH  is set regardless. If your shell is  tcsh , add the following line to your  .tcshrc  file: setenv PATH ${PATH}:/usr/local/mysql/bin If the appropriate startup file does not exist in your home directory, create it with a text editor. After modifying your  PATH  setting, open a new console window on Windows or log in again on Unix so that the setting goes into effect. 381