pandoc: 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/pandoc - from package: pandoc

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

On Debian possible default full paths are:

/usr/bin/pandoc - from package: pandoc

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

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