GNU/Linux


cecho – a function to print using different colors in bash

The following script can be used to print colored text in bash.
You can use it in any script without copy pasting everything in it by executing the following command source cecho.sh.
Doing so, it will load to your script the functions that are defined in cecho.sh, making them available for you to use (something like including code in C, with some caveats).

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#!/bin/bash

# The following function prints a text using custom color
# -c or --color define the color for the print. See the array colors for the available options.
# -n or --noline directs the system not to print a new line after the content.
# Last argument is the message to be printed.
cecho () {

    declare -A colors;
    colors=(\
        ['black']='\E[0;47m'\
        ['red']='\E[0;31m'\
        ['green']='\E[0;32m'\
        ['yellow']='\E[0;33m'\
        ['blue']='\E[0;34m'\
        ['magenta']='\E[0;35m'\
        ['cyan']='\E[0;36m'\
        ['white']='\E[0;37m'\
    );

    local defaultMSG="No message passed.";
    local defaultColor="black";
    local defaultNewLine=true;

    while [[ $# -gt 1 ]];
    do
    key="$1";

    case $key in
        -c|--color)
            color="$2";
            shift;
        ;;
        -n|--noline)
            newLine=false;
        ;;
        *)
            # unknown option
        ;;
    esac
    shift;
    done

    message=${1:-$defaultMSG};   # Defaults to default message.
    color=${color:-$defaultColor};   # Defaults to default color, if not specified.
    newLine=${newLine:-$defaultNewLine};

    echo -en "${colors[$color]}";
    echo -en "$message";
    if [ "$newLine" = true ] ; then
        echo;
    fi
    tput sgr0; #  Reset text attributes to normal without clearing screen.

    return;
}

warning () {

    cecho -c 'yellow' "$@";
}

error () {

    cecho -c 'red' "$@";
}

information () {

    cecho -c 'blue' "$@";
}

 

Usage

Function cecho accepts the options to set the color and to control if a new line should be print.
Parameter -c or --color define the color for the print. See the array colors for the available options.
Parameter -n or --noline directs the system not to print a new line after the content.
The last parameter is the string message to be printed.
Functions warning, error and information are using cecho to print in color.
These three functions always print a new line and they have hardcoded one color set for each.

Example


#Get the name of the script currently being executed

scriptName=$(basename $(test -L "$0" && readlink "$0" || echo "$0"));

#Get the directory where the script currently being executed resides

scriptDirDIR=$(cd $(dirname "$0") && pwd);

#Print in blue color with no new line

cecho -n -c 'blue' "$scriptDir";

#Print in red color with a new line following the message

cecho -c 'red' "$scriptName";

#Using the information() function to print in blue followed by a new line

information ‘End of script’;


Install terminator in CentOS 6.5 (64bit)

We installed CentOS 6.5 (64bit) using this ISO, which we downloaded from http://vault.centos.org/6.5/isos/x86_64/

Once we got the OS started, we executed yum update -y to update all installed packages that were older than the versions in the repositories.
After the update process was complete, we then tried to install terminator using yum.

Executing yum install -y terminator resulted in an error:

Loaded plugins: fastestmirror, refresh-packagekit, security
Setting up Install Process
Loading mirror speeds from cached hostfile
* base: mirror.us.leaseweb.net
* extras: mirror.us.leaseweb.net
* updates: mirror.us.leaseweb.net
No package terminator available.
Error: Nothing to do

To solve the problem we needed to install the Extra Packages for Enterprise Linux (EPEL) repository using yum install -y epel-release.

After the installation was done, we executed yum install -y terminator once more and the installation of terminator succeeded.


Downgrade texinfo on CentOS 7.0 (64bit) to version 4.13

Recently we had to download texinfo from version 5.1 to any version less than version 5 series.
We used texinfo version 4.13 which is the latest in the version 4 series.

We were trying to compile some tools using an older version of gcc. Instead of using 4.8.5, we used 4.8.2 to achieve our goal and that caused a problem with some .texi files.

Methodology


#Making sure we are not missing any 32bit libraries since we are on a 64bit machine
yum install glibc.i686 ncurses-libs.i686;
#Download the source code
wget http://ftp.gnu.org/gnu/texinfo/texinfo-4.13.tar.gz;
#Extract the files
tar -zxf texinfo-4.13.tar.gz;
#Navigate to the folder
cd texinfo-4.13;
#Configure the installation and make all necessary checks
./configure;
#Build
make;
#Install
sudo make install;


Downgrade gcc on CentOS 7.0 (64bit) to version 4.8.2

Recently we had to download gcc from version 4.8.5 to 4.8.2.

We were trying to compile some tools and they required using that older version of gcc.
To compile the old version of the gcc we used the version version that was shipped with the distribution.

Methodology

#Making sure we are not missing any 32bit libraries since we are on a 64bit machine
yum install glibc.i686 ncurses-libs.i686;
#Download the source code
wget http://ftp.gnu.org/gnu/gcc/gcc-4.8.2/gcc-4.8.2.tar.gz;
#Extract the files
tar -xvf gcc-4.8.2.tar.gz;
#Navigate to the folder
cd gcc-4.8.2/;
#Make sure we have all dependencies met
./contrib/download_prerequisites;
#Configure the installation and assign the installation folder to be /usr/local/gcc/4.8.2. Finally make all necessary checks before compilation.
./configure --prefix=/usr/local/gcc/4.8.2;
#Build
make;
#Install
sudo make install;