alembic: 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/alembic - from package: python-alembic

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

On Debian possible default full paths are:

/usr/bin/alembic - from package: alembic

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

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