The Filesystem Hierarchy Standard (FHS) defines a standard layout to organize various kinds of application and OS related data in a predictable and common way [1].
A basic knowledge of the FHS will help you to find application or OS related data more easily. If you are a developer, it also provides a good orientation for organizing your own applications in a maintainable way, e.g. as ubuntu package.
/bin – essential user commands
/boot – OS boot loader
/dev – devices (everything is a file principle)
/etc – system configuration
/home – user data
/lib – essentail shared libraries
/media – mount point for removable media
/mnt – mount point for temporarily mounted filesystems
/opt – add-on applications
/root – home of root
/run – run time variable data
/sbin – system binaries
/srv – data for services provided by the system
/tmp – temporary data
/proc – is a virtual filesystem
/usr – secondary hierarchy
bin – Most user commands
lib – Libraries
local – Local hierarchy (empty after main installation)
sbin – Non-vital system binaries
share – Architecture-independent data
/var – variable data
cache – Application cache data
lib – Variable state information
local – Variable data for /usr/local
lock – Lock files
log – Log files and directories
opt – Variable data for /opt
run – Data relevant to running processes
spool – Application spool data
tmp -Temporary files preserved between system reboots
Find more
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