Ubuntu follows the filesystem hierarchy structure. The location where software gets installed depends on how you install it. According to the FHS, /usr hierarchy is reserved for the software provided by the Linux distribution. By convention, /usr/local is reserved for software compiled and installed manually. The /usr/local directory should contain a structure very similar to that of the /usr directory. The /usr/local directory provides a location for software installation that overrides versions of the same packages installed in the /usr directory structure, because system software updates often overwrite software in /usr without prejudice.
Default Installation
Software installed using Ubuntu Software Center generally gets installed to the default locations. Libraries will end up in /usr/lib/ and the executable in /bin (essential command binaries available in single user mode; e.g., cat, ls, cp), /usr/bin or /usr/sbin (non-essential command binaries).
Linux distribution packages get installed in /usr directory tree. For instance, if you installed the Autoconf package using the command sudo apt-get install autoconf, the package binaries would be installed into the /usr/bin directory. When you install your hand-built Autoconf binaries, they’ll go into /usr/local/bin, by default.
The direct equivalent of Program Files though is probably /opt or maybe /usr/share. That directory contains the various support files for most programs.
Manual Installation
If you are compiling your own software then you ultimately control the installation location. By convention, software compiled and installed manually (not through a package manager) is installed in /usr/local. Some packages will install their files into existing directories such as /usr/local/sbin and /usr/local/etc. These are simply default locations and can be changed during compilation. Your source code should not be stored in /usr/src as that is designated for system software such as the kernel.
Finally, you need to ensure that your installation location is included in your PATH. If you decide to install your package in /opt but it’s not in your PATH your shell won’t find the executable. It’s most often the case that /usr/local/bin is positioned in your PATH environment variable before /usr/bin. This allows your locally built and installed programs to override the ones installed by your distribution’s package manager.
Locate Application
To know where the executable is you can run whereis or which or type. For instance, below example find the installation of directory of bash.
If the installed program is in PATH, above command returns the path as shown above. If the installed application it is not in PATH, then it’s best to look for it with locate command. For example to find anything named git present in bin folder, use below command
locate -b git | fgrep -w bin