decolor: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/lib/ruby/gems/1.8/gems/term-ansicolor-1.0.7/bin/decolor - from package: rubygem-term-ansicolor

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/decolor - from package: ruby-term-ansicolor

You may install the required package with command apt-get install {package}

Error in other languages:
decolor: bevel nie gevind nie
decolor: comandă negăsită
decolor: comando não encontrado
decolor: commande introuvable
decolor: command not found
decolor: käsku ei ole
decolor: không tìm thấy lệnh
decolor: komanda nerasta
decolor: Kommando nicht gefunden.
decolor: kommandot finns inte
decolor: komut yok
decolor: nie znaleziono polecenia
decolor: níor aimsíodh an t-ordú
decolor: no se encontró la orden
decolor: no s'ha trobat l'ordre
decolor: opdracht niet gevonden
decolor: parancs nem található
decolor: perintah tidak ditemukan
decolor: príkaz nenájdený
decolor: příkaz nenalezen
decolor: команда не найдена
decolor: командата не е открита
decolor: 命令找不到
decolor: コマンドが見つかりません