source-highlight-settings: 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/bin/source-highlight-settings - from package: source-highlight

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

On Debian possible default full paths are:

/usr/bin/source-highlight-settings - from package: source-highlight

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

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