SSH – Set Local Terminal Colors to Match Remote Machine

colorssshterminal

I have a color scheme that I like for when I'm in a terminal, but I ssh into the machine I work on from multiple sources (locally, PuTTY, my netbook, etc.) and I want to maintain the same color scheme throughout. Is this possible?

I especially want it in PuTTY; it's difficult to change PuTTY colors.

Best Answer

Colors in terminals are determined in two steps:

the program running in the terminal tells the terminal to use a certain color number;
the terminal translates each color number into a color value.

Xterm has an escape sequence to change the color value associated with a color number. I don't remember whether PuTTY supports this sequence; I know Mintty does.

set_color_value () {
  printf "\\e]4;$1;$2\\a"
}
set_color_value 4 '#6495ed'  # set color 4 (blue) to CornflowerBlue

These settings won't survive a terminal reset. You can overcome this difficulty by appending the cursor configuration changing sequence to your terminal's reset string.

On a terminfo-based system using ncurses, save your terminal's terminfo settings to a file with infocmp >>~/etc/terminfo.txt. Edit the description to change the rs1 (basic reset) sequence, e.g. replace rs1=\Ec by rs1=\Ec\E]4;4;#6495ed\E\\. With some programs and settings, you may need to change the rs2 (full reset) as well. Then compile the terminfo description with tic ~/etc/terminfo.txt (this writes under the directory $TERMINFO, or ~/.terminfo if unset).
On a termcap-based system, grab the termcap settings from your termcap database (typically /etc/termcap). Change the is (basic reset) and rs (full reset) sequences to append your settings, e.g. :is=\Ec\Ec\E]4;4;#6495ed\E\\:. Set the TERMCAP environment variable to the edited value (beginning and ending with :).

Now you can put something like this in your ~/.profile:

if [ "$(ps -p $PPID -o comm=)" = sshd ] &&
   [ "$TERM" = "xterm" ]; then
  set_color_value … # set color scheme
  TERMCAP=…  # if necessary
fi

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I don't know about window titles, but I have been trying to have my system do something on terminating a ssh session—actually, after terminating a ssh session. In short: it doesn't work like that. Basically you have three choices:

Write a wrapper around ssh, i.e., an executable shell script named ssh that takes precedence over /usr/bin/ssh in your $PATH which contains the line exec /usr/bin/ssh $@ somewhere in its middle. This enables you to have your shell do some stuff before and after the effective ssh binary is run, while keeping th eoverhead to a minimum.
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Bash – Why the differences in color between SSH terminal sessions in OSX

Copy this part into you CentOS .bashrc:

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)
    color_prompt=yes
    else
    color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[    \033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

The ${debian_chroot:+($debian_chroot)} part won't work, though and can be removed (but it won't hurt anything by staying there, it just evaluates to an empty string).

Best Answer

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