On some systems that have shared libraries (which most systems do) you need to tell your system how to find the newly installed shared libraries. The systems on which this is not necessary include BSD/OS, FreeBSD, HP-UX, IRIX, Linux, NetBSD, OpenBSD, Tru64 UNIX (formerly Digital UNIX), and Solaris.
The method to set the shared library search path varies between platforms, but the most widely usable method is to set the environment variable LD_LIBRARY_PATH like so: In Bourne shells (sh, ksh, bash, zsh)
LD_LIBRARY_PATH=/usr/local/pgsql/lib export LD_LIBRARY_PATH
or in csh or tcsh
setenv LD_LIBRARY_PATH /usr/local/pgsql/lib
Replace /usr/local/pgsql/lib with whatever you set --libdir to in step 1. You should put these commands into a shell start-up file such as /etc/profile or ~/.bash_profile. Some good information about the caveats associated with this method can be found at http://www.visi.com/~barr/ldpath.html.
On some systems it might be preferable to set the environment variable LD_RUN_PATH before building.
On Cygwin, put the library directory in the PATH or move the .dll files into the bin/ directory.
If in doubt, refer to the manual pages of your system (perhaps ld.so or rld). If you later on get a message like
psql: error in loading shared libraries libpq.so.2.1: cannot open shared object file: No such file or directory
then this step was necessary. Simply take care of it then.
(or equivalent directory) after installation to enable the run-time linker to find the shared libraries faster. Refer to the manual page of ldconfig for more information. On FreeBSD, NetBSD, and OpenBSD the command is
/sbin/ldconfig -m /usr/local/pgsql/lib
instead. Other systems are not known to have an equivalent command.
If you installed into /usr/local/pgsql or some other location that is not searched for programs by default, you should add /usr/local/pgsql/bin (or whatever you set --bindir to in step 1) into your PATH. Strictly speaking, this is not necessary, but it will make the use of PostgreSQL much more convenient.
To do this, add the following to your shell start-up file, such as ~/.bash_profile (or /etc/profile, if you want it to affect every user):
PATH=/usr/local/pgsql/bin:$PATH export PATH
If you are using csh or tcsh, then use this command:
set path = ( /usr/local/pgsql/bin $path )
MANPATH=/usr/local/pgsql/man:$MANPATH export MANPATH
The environment variables PGHOST and PGPORT specify to client applications the host and port of the database server, overriding the compiled-in defaults. If you are going to run client applications remotely then it is convenient if every user that plans to use the database sets PGHOST. This is not required, however: the settings can be communicated via command line options to most client programs.