echo(1) "export PGHOST=localhost" >> ~/.bash_profile
display a line of text
Echo the STRING(s) to standard output.
Before a command is executed, its input and output may be redirected using a special notation interpreted
by  the  shell.   Redirection  may  also  be used to open and close files for the current shell execution
environment.  The following redirection operators may precede or appear anywhere within a simple  command
or may follow a command.  Redirections are processed in the order they appear, from left to right.

Appending Redirected Output
    Redirection of output in this fashion causes the file whose name results from the expansion of word to be
    opened  for  appending  on  file  descriptor  n,  or  the standard output (file descriptor 1) if n is not
    specified.  If the file does not exist it is created.

    The general format for appending output is:

source manpages: echo