sort: 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:

/bin/sort - from package: coreutils

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

On Debian possible default full paths are:

/usr/lib/plan9/bin/sort - from package: 9base
/usr/bin/sort - from package: coreutils

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

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