gtk cedilha
How to use the letter c cedilla with the international keyboard layout.
Como usar a letra c cedilha com o layout de teclado internacional.
Works on Ubuntu 8.04.
May work on other versions of Unix, GNU/Linux, Debian, Ubuntu, GTK+ and GNOME.
When using programs created with GTK+, like those in GNOME, the dead key letters are mapped by GTK+. To get the c cedilla letter, "ç", to work by pressing dead acute and c keys, like many are used to do in Brazil, you can set the environment variable GTK_IM_MODULE to cedilla. By putting a line with GTK_IM_MODULE=cedilla in /etc/environment , the GNOME session receives this environment variable and GTK+ outputs "ç" after typing the acute and c keys in sequence.
For other programs which don't use GTK+, you still need to change the Compose file of X11.
procedure
Execute the following command in a terminal.
sudo sh -c "echo GTK_IM_MODULE=cedilla >> /etc/environment"
references
Owen Taylor, GTK+ developer who wrote imcedilla.c .
http://mail.gnome.org/archives/gtk-i18n-list/2003-October/msg00006.html
PAM environment variables manual page
man pam_env
Ubuntu Community Documentation
https://help.ubuntu.com/community/EnvironmentVariables#System-wide%20environment%20variables