-if [ $hostname != asp -a $hostname != systemofadown ]; then
- sed 's/Enable 256 color/Disable 256 color/;
- s/screen-256color/screen/' screenrc > screenrc.tmp
- mv screenrc.tmp screenrc
-fi
-# I use some features of screen which are only in Git. Drop them on machines
-# which have older versions. They are marked as "(GIT)".
-if [ $hostname != asp ]; then
+# As screen-256color is not widely supported use it only on machines where the
+# matching terminfo entry is available. This also requires a terminal emulator
+# which supports 256 colors. Also used for tmux.
+use_256colors=
+if terminal_available screen-256color; then
+ # Called through SSH connection, assume the local system supports 256
+ # colors.
+ if test -n "$SSH_CONNECTION"; then
+ use_256colors=1
+ # We have rxvt-unicode installed, check if it supports 256 colors.
+ elif installed urxvt; then
+ # Thanks to deryni in #rxvt-unicode on Freenode (2012-10-14 22:54
+ # CEST) for the strings/grep idea. The grep check is for "correct" 256
+ # rxvt-unicode binaries (e.g. Debian's rxvt-unicode-256color), the
+ # terminal_info check for manual installations which modify
+ # rxvt-unicode's terminfo entry.
+ urxvt_path=`installed_path urxvt`
+ urxvt_grep=`strings "$urxvt_path" | grep '^TERM=rxvt-'`
+ if test x"$urxvt_grep" = 'xTERM=rxvt-unicode-256color' \
+ || terminal_info rxvt-unicode \
+ | grep -F 'colors#256' >/dev/null; then
+ use_256colors=1
+ fi
+ # Check if XTerm supports 256 colors (not a perfect check, but most XTerm
+ # support 256 colors).
+ elif terminal_available xterm-256color; then
+ use_256colors=1
+ fi
+fi
+if test -z "$use_256colors"; then
+ echo screenrc: removing 256 colors
+ sed_i 's/Enable 256 color/Disable 256 color/;
+ s/screen-256color/screen/' screenrc
+fi
+# Some options are only necessary when running as root. They are marked as
+# "(ROOT)".
+if test "`id -u`" -ne 0; then
+ echo screenrc: removing root options
+ grep_i -v '(ROOT)' screenrc
+fi
+# I use some features of GNU screen which are only in Git or very recent GNU
+# screen versions. Drop them on machines which have older versions. They are
+# marked as "(GIT)".
+if test ! -d "$HOME/development/shell/screen"; then