runghc: 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/runghc - from package: ghc-compiler

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

On Debian possible default full paths are:

/usr/bin/runghc - from package: ghc
/usr/lib/ghc/bin/runghc - from package: ghc

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

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