installer: use terminfo for portable escape sequences

Do not use terminal visual effects if not connected to a terminal.

tools/install.sh

 set -e
 
-BLUE="\033[0;34m"
-GREEN="\033[0;32m"
-YELLOW="\033[0;33m"
-NOCOLOR="\033[0m"
+# Use colors, but only if connected to a terminal, and that terminal
+# supports them.
+ncolors=$(tput colors)
+if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
+  RED=="$(tput setaf 1)"
+  GREEN="$(tput setaf 2)"
+  YELLOW="$(tput setaf 3)"
+  BLUE="$(tput setaf 4)"
+  BOLD="$(tput bold)"
+  NORMAL="$(tput sgr0)"
+else
+  RED=""
+  GREEN=""
+  YELLOW=""
+  BLUE=""
+  BOLD=""
+  NORMAL=""
+fi
 
 if [ ! -n "$ZSH" ]; then
   ZSH=~/.oh-my-zsh
 fi
 
 if [ -d "$ZSH" ]; then
-  printf "${YELLOW}You already have Oh My Zsh installed.${NOCOLOR} You'll need to remove $ZSH if you want to install\n"
+  printf "${YELLOW}You already have Oh My Zsh installed.${NORMAL}\n"
+  printf "You'll need to remove $ZSH if you want to re-install.\n"
   exit
 fi
 
-printf "${BLUE}Cloning Oh My Zsh...${NOCOLOR}\n"
+printf "${BLUE}Cloning Oh My Zsh...${NORMAL}\n"
 hash git >/dev/null 2>&1 && env git clone --depth=1 https://github.com/robbyrussell/oh-my-zsh.git $ZSH || {
   printf "git not installed\n"
   exit
 }
 
-printf "${BLUE}Looking for an existing zsh config...${NOCOLOR}\n"
+printf "${BLUE}Looking for an existing zsh config...${NORMAL}\n"
 if [ -f ~/.zshrc ] || [ -h ~/.zshrc ]; then
-  printf "${YELLOW}Found ~/.zshrc.${NOCOLOR} ${GREEN}Backing up to ~/.zshrc.pre-oh-my-zsh${NOCOLOR}\n";
+  printf "${YELLOW}Found ~/.zshrc.${NORMAL} ${GREEN}Backing up to ~/.zshrc.pre-oh-my-zsh${NORMAL}\n";
   mv ~/.zshrc ~/.zshrc.pre-oh-my-zsh;
 fi
 
-printf "${BLUE}Using the Oh My Zsh template file and adding it to ~/.zshrc${NOCOLOR}\n"
+printf "${BLUE}Using the Oh My Zsh template file and adding it to ~/.zshrc${NORMAL}\n"
 cp $ZSH/templates/zshrc.zsh-template ~/.zshrc
 sed -i -e "/^export ZSH=/ c\\
 export ZSH=$ZSH
 " ~/.zshrc
 
-printf "${BLUE}Copying your current PATH and adding it to the end of ~/.zshrc for you.${NOCOLOR}\n"
+printf "${BLUE}Copying your current PATH and adding it to the end of ~/.zshrc for you.${NORMAL}\n"
 sed -i -e "/export PATH=/ c\\
 export PATH=\"$PATH\"
 " ~/.zshrc
 
 TEST_CURRENT_SHELL=$(expr "$SHELL" : '.*/\(.*\)')
 if [ "$TEST_CURRENT_SHELL" != "zsh" ]; then
-    printf "${BLUE}Time to change your default shell to zsh!${NOCOLOR}\n"
+    printf "${BLUE}Time to change your default shell to zsh!${NORMAL}\n"
     chsh -s $(grep /zsh$ /etc/shells | tail -1)
 fi
 unset TEST_CURRENT_SHELL
@@ -59,5 +74,5 @@ echo 'p.s. Follow us at http://twitter.com/ohmyzsh.'
 echo ''
 echo 'p.p.s. Get stickers and t-shirts at http://shop.planetargon.com.'
 echo ''
-printf "${NOCOLOR}"
+printf "${NORMAL}"
 env zsh

tools/upgrade.sh

-printf '\033[0;34m%s\033[0m\n' "Upgrading Oh My Zsh"
+
+# Use colors, but only if connected to a terminal, and that terminal
+# supports them.
+ncolors=$(tput colors)
+if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
+  RED=="$(tput setaf 1)"
+  GREEN="$(tput setaf 2)"
+  YELLOW="$(tput setaf 3)"
+  BLUE="$(tput setaf 4)"
+  BOLD="$(tput bold)"
+  NORMAL="$(tput sgr0)"
+else
+  RED=""
+  GREEN=""
+  YELLOW=""
+  BLUE=""
+  BOLD=""
+  NORMAL=""
+fi
+
+printf "${BLUE}%s${NORMAL}\n" "Upgrading Oh My Zsh"
 cd "$ZSH"
 if git pull --rebase --stat origin master
 then
-  printf '\033[0;32m%s\033[0m\n' '         __                                     __   '
-  printf '\033[0;32m%s\033[0m\n' '  ____  / /_     ____ ___  __  __   ____  _____/ /_  '
-  printf '\033[0;32m%s\033[0m\n' ' / __ \/ __ \   / __ `__ \/ / / /  /_  / / ___/ __ \ '
-  printf '\033[0;32m%s\033[0m\n' '/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / / '
-  printf '\033[0;32m%s\033[0m\n' '\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/  '
-  printf '\033[0;32m%s\033[0m\n' '                        /____/                       '
-  printf '\033[0;34m%s\033[0m\n' 'Hooray! Oh My Zsh has been updated and/or is at the current version.'
-  printf '\033[0;34m%s\033[1m%s\033[0m\n' 'To keep up on the latest news and updates, follow us on twitter: ' 'http://twitter.com/ohmyzsh'
-  printf '\033[0;34m%s\033[1m%s\033[0m\n' 'Get your Oh My Zsh swag at: ' 'http://shop.planetargon.com/'
+  printf '%s' "$GREEN"
+  printf '%s\n' '         __                                     __   '
+  printf '%s\n' '  ____  / /_     ____ ___  __  __   ____  _____/ /_  '
+  printf '%s\n' ' / __ \/ __ \   / __ `__ \/ / / /  /_  / / ___/ __ \ '
+  printf '%s\n' '/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / / '
+  printf '%s\n' '\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/  '
+  printf '%s\n' '                        /____/                       '
+  printf "${BLUE}%s\n" "Hooray! Oh My Zsh has been updated and/or is at the current version."
+  printf "${BLUE}${BOLD}%s${NORMAL}\n" "To keep up on the latest news and updates, follow us on twitter: http://twitter.com/ohmyzsh"
+  printf "${BLUE}${BOLD}%s${NORMAL}\n" "Get your Oh My Zsh swag at:  http://shop.planetargon.com/"
 else
-  printf '\033[0;31m%s\033[0m\n' 'There was an error updating. Try again later?'
+  printf "${RED}%s${NORMAL}\n" 'There was an error updating. Try again later?'
 fi