You can install Tree using apt-get or yum depending on your distribution. On Ubuntu 14.04 we'll be using apt-get.
sudo apt-get update && apt-get install tree
On RHEL/CentOS
yum update -y && yum install tree -y
Once installed, use the command 'tree' followed by the directory path to view an indented hierarchical listing of your files. Piping the command into less will let you take a good look around.
root@nothing:~# tree /var/ | less /var/ ├── backups │ ├── apt.extended_states.0 │ ├── apt.extended_states.1.gz │ ├── apt.extended_states.2.gz │ ├── apt.extended_states.3.gz │ ├── dpkg.status.0 │ ├── dpkg.status.1.gz │ ├── dpkg.status.2.gz │ ├── dpkg.status.3.gz │ ├── group.bak │ ├── gshadow.bak │ ├── passwd.bak │ └── shadow.bak ├── cache │ ├── apache2 │ │ └── mod_cache_disk │ ├── apparmor ...
Or, if you'd like to impress your friends, you could use the following for a similar output:
ls -R /path/to/dir | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/'