The executable program psql is in the directory /usr/pgsql-9.2/bin, and that directory isn't included in the path by default, so we have to tell our shell (terminal) program where to find psql. When most of the packages are installed, they are added to an existing path, such as /usr/local/bin, but not this program.
So we need to add the program's path to the shell PATH variable if we do not want to have to type the complete path to the program every time we execute it.
This line should typically be added to the shell startup script, which for the bash shell will be in the file ~/.bashrc.
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