runhaskell: command not found

Have You tried accessing the binary with the full path?

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/runhaskell - from package: ghc-compiler

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

On Debian possible default full paths are:

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

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