fold: 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/fold - from package: coreutils

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

On Debian possible default full paths are:

/usr/bin/fold - from package: coreutils

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

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