To know what is your installation folder or Redmine is essential to be able to install extensions or to enhance Redmine.
Redmine install directory under Linux
Under Linux we can often easily identify the installation folder.
Any Linux distribution
There are mutliple ways to find out the installation folder.
Find installation folder by the running processes
ps aux|grep [Rr]edmine
It shall return you processes which are having something with redmine in the process command or path. If here you are not finding the proper paths, you shall take the process number and search for the open files.
ps aux|grep redmine root 745 0.0 0.0 14756 1036 pts/0 S+ 14:57 0:00 grep --color=auto redmine www-data 5998 0.1 7.7 594064 158880 ? Sl 09:27 0:31 Passenger RubyApp: /usr/share/redmine postgres 6005 0.0 2.2 207496 46588 ? Ss 09:27 0:07 postgres: redmine redmine_default 127.0.0.1(37148) idle
In the above case we already see the path /usr/share/redmine. But let us assume it is not clear. We will execute for the ruby/passenger process:
lsof |grep 5998
lsof |grep 5998 |grep [Rr]edmine
and we get also a bunch of open files back of /usr/share/redmine. And bingo, you have your installation folder found.
Find installation folder on debian based distributions like Ubuntu
For debian based projects you can use this command if redmine is already installed
for package in $(dpkg --list|grep "redmine"|awk -P '{print $2}'); do dpkg-query -L $package|sort;done |less