Detecting the output stream type of a shell script

Question

I\'m writing a shell script that uses ANSI color characters on the command line.

Example: example.sh

#!/bin/tcsh
printf \"\\033[31m Succ         


        

Answer 1

The detection of the output stream type is covered in the question detect if shell script is running through a pipe.

Having decided that you are talking to terminal, then you can use tput to retrieve the correct escape codes for the particular terminal you are using - this will make the code more portable.

An example script (in bash I am afraid, as tcsh is not my forte) is given below.

#!/bin/bash

fg_red=
fg_green=
fg_yellow=
fg_blue=
fg_magenta=
fg_cyan=
fg_white=
bold=
reverse=
attr_end=

if [ -t 1 ]; then
    fg_red=$(tput setaf 1)
    fg_green=$(tput setaf 2)
    fg_yellow=$(tput setaf 3)
    fg_blue=$(tput setaf 4)
    fg_magenta=$(tput setaf 5)
    fg_cyan=$(tput setaf 6)
    fg_white=$(tput setaf 7)
    bold=$(tput bold)
    reverse=$(tput rev)
    underline=$(tput smul)
    attr_end=$(tput sgr0)
fi

echo "This is ${fg_red}red${attr_end}"
echo "This is ${fg_green}green${attr_end}"
echo "This is ${fg_yellow}yellow${attr_end}"
echo "This is ${fg_blue}blue${attr_end}"
echo "This is ${fg_magenta}magenta${attr_end}"
echo "This is ${fg_cyan}cyan${attr_end}"
echo "This is ${fg_white}white${attr_end}"
echo "This is ${bold}bold${attr_end}"
echo "This is ${reverse}reverse${attr_end}"
echo "This is ${underline}underline${attr_end}"

For more information see "man tput" and "man terminfo" - there are all sorts of escape codes to play with.