dos2unix: 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/dos2unix - from package: dos2unix

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

On Debian possible default full paths are:

/usr/bin/dos2unix - from package: dos2unix

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

Error in other languages:
dos2unix: bevel nie gevind nie
dos2unix: comandă negăsită
dos2unix: comando não encontrado
dos2unix: commande introuvable
dos2unix: command not found
dos2unix: käsku ei ole
dos2unix: không tìm thấy lệnh
dos2unix: komanda nerasta
dos2unix: Kommando nicht gefunden.
dos2unix: kommandot finns inte
dos2unix: komut yok
dos2unix: nie znaleziono polecenia
dos2unix: níor aimsíodh an t-ordú
dos2unix: no se encontró la orden
dos2unix: no s'ha trobat l'ordre
dos2unix: opdracht niet gevonden
dos2unix: parancs nem található
dos2unix: perintah tidak ditemukan
dos2unix: príkaz nenájdený
dos2unix: příkaz nenalezen
dos2unix: команда не найдена
dos2unix: командата не е открита
dos2unix: 命令找不到
dos2unix: コマンドが見つかりません