How to find if a program is installed or not?
 

I have difficulties sometimes figuring out if a program/product/
package is installed or not. Is there a standard way of finding
that out? I know in M$ Windows you can alwys look for some
.exe to run. But not sure in Linux. Only thing that I have been
is doing so far is to find out what all are the executable files
using 'ls -l'. Often times it gets very annoying.
Some of the products I am keen to see if they are installed are
are:
Apache
Python
Perl
Wine
Oss drivers
etc.

Any thoughts on this?

whereis programname
or
locate programname
or
ls /usr/bin/*programname*
or (only for rpm-installed programs)
rpm -qa | grep programname

You need to run updatedb before you use the locate command if you haven't done so already. The slocate.db is built by running updatedb, and this is what locate uses to find things.

rpm -qa | grep <programname> is usually the best way to find things that are already installed...assuming, like rverlander said, it was installed using rpm.

Ryan

So, if I installed a program using .tar.gz, will it not be list as installed
in rpm?
If not, is there a way to connect rpm database with other installa-
tions?
And, most importantly, how DO I UNINSTALL PROGRAMS?

1. Nope, it only will if u make your own RPM
2. Go to source build directory and type: