Pipable command to print in color?

I'm a bit new to bash scripting, and I'm wondering if there is a program or built-in command to pipe to that will print in a specified color? Or is there an echo argument to do so?

Like I could do:

echo Hi | commandhere -arguement blue

and it would print "Hi" in the color blue?

I don't know of any utility for colored printing itself, but you can do it easily with a shell function like this:

# colorize stdin according to parameter passed (GREEN, CYAN, BLUE, YELLOW)
colorize(){
    GREEN="\033[0;32m"
    CYAN="\033[0;36m"
    GRAY="\033[0;37m"
    BLUE="\033[0;34m"
    YELLOW="\033[0;33m"
    NORMAL="\033[m"
    color=\$${1:-NORMAL}
    # activate color passed as argument
    echo -ne "`eval echo ${color}`"
    # read stdin (pipe) and print from it:
    cat
    # Note: if instead of reading from the pipe, you wanted to print
    # the additional parameters of the function, you could do:
    # shift; echo $*
    # back to normal (no color)
    echo -ne "${NORMAL}"
}
echo hi | colorize GREEN

If you want to check other colors, take a look at this list. You can add support for any color from there, simply creating an additional variable at this function with the correct name and value.

I created this function that I use in bash scripts.

# Function to echo in specified color
echoincolor () {
    case $1 in
        "red") tput setaf 1;;
        "green") tput setaf 2;;
        "orange") tput setaf 3;;
        "blue") tput setaf 4;;
        "purple") tput setaf 5;;
        "cyan") tput setaf 6;;
        "gray" | "grey") tput setaf 7;;
        "white") tput setaf 8;;
    esac
    echo "$2";
    tput sgr0
}

Then I just call it like this echoincolor green "This text is in green!"

Alternatively, use printf

# Function to print in specified color
colorprintf () {
    case $1 in
        "red") tput setaf 1;;
        "green") tput setaf 2;;
        "orange") tput setaf 3;;
        "blue") tput setaf 4;;
        "purple") tput setaf 5;;
        "cyan") tput setaf 6;;
        "gray" | "grey") tput setaf 7;;
        "white") tput setaf 8;;
    esac
    printf "$2";
    tput sgr0
}

Then just call it like this colorprintf green "This text is in green!"

Note, echo provides a trailing new line while printf does not.

I use this old script, names hilite.pl, taken from the web, already with the "unknown author" line!

#!/usr/bin/perl -w
### Usage: hilite <ansi command> <target string>
### Purpose: Will read text from standard input and perform specified highlighting
### command before displaying text to standard output.
### License: GNU GPL
# unknown author 

$|=1; # don't buffer i/o
$command = "$ARGV[0]";
$target = "$ARGV[1]";
$color = "\e[" . $command . "m";
$end = "\e[0m";

while(<STDIN>) {
    s/($target)/$color$1$end/;
    print $_;
}

Then i can use it in pipes, to "hilite" log output or other things, using regexp/PCRE:

 echo 'hello color world!!' | hilite.pl 34 "[Hh]el[^ ]*" | hilite.pl 43 .orld | hilite.pl 32 "\scolor\s"

This will paint hello in blue, color in green and world in yellow background

You can see the color list with (you can expand the bash expression to {01..255} if you want):

for i in {01..10}  {30..49} {90..110}  ; do echo $i | hilite.pl $i $i ; done

Pipable command to print in color?

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