I use Linux Mint Mate 17, which is based on Ubuntu 14.04, and I want to map my right Alt to act as a Ctrl key since I can reach it with my right thumb which is more comfortable. How can I do that?I tried to search online, however most guides are based on using Xmodmap which seems to be deprecated. Some others use xkb, but I eventually gave up configuring it. One of the attempts was to add something likekey <ALTGR> { [ Control_L ] };to xkb_symbols pc105 section of /usr/share/X11/xkb/symbols/pc, but it didn't work. In fact, I understand neither why I should use specifically this file (there are a lot of them in symbols directory, and I've found include pc line only in macintosh_vndr/apple file), nor where I should learn the right name of the key -- RALT or ALTGR is just my suggestion, nor what the section name pc105 means.After some more searching, I found out that the following command does what  I want:setxkbmap -option ctrl:ralt_rctrlHowever, it obviously works only for the current session. I tried to add it to my .profile, but it didn't help. What is the right way to do this?
Map right Alt to Ctrl key
keyboard layout;xkb