ecryptfs-manager: command not found

Have You tried accessing the binary with the full path?

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/ecryptfs-manager - from package: ecryptfs-utils

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

On Debian possible default full paths are:

/usr/bin/ecryptfs-manager - from package: ecryptfs-utils

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